diff --git a/src/controller/python/chip/yaml/constraints.py b/src/controller/python/chip/yaml/constraints.py
index 933d74f..49ac8c9 100644
--- a/src/controller/python/chip/yaml/constraints.py
+++ b/src/controller/python/chip/yaml/constraints.py
@@ -36,7 +36,7 @@
 class _LoadableConstraint(BaseConstraint):
     '''Constraints where value might be stored in VariableStorage needing runtime load.'''
 
-    def __init__(self, value, field_type, variable_storage: VariableStorage):
+    def __init__(self, value, field_type, variable_storage: VariableStorage, config_values: dict):
         self._variable_storage = variable_storage
         # When not none _indirect_value_key is binding a name to the constraint value, and the
         # actual value can only be looked-up dynamically, which is why this is a key name.
@@ -50,8 +50,8 @@
         if isinstance(value, str) and self._variable_storage.is_key_saved(value):
             self._indirect_value_key = value
         else:
-            self._value = Converter.convert_yaml_type(
-                value, field_type)
+            self._value = Converter.parse_and_convert_yaml_value(
+                value, field_type, config_values)
 
     def get_value(self):
         '''Gets the current value of the constraint.
@@ -112,8 +112,9 @@
 
 
 class _ConstraintMinValue(_LoadableConstraint):
-    def __init__(self, min_value, field_type, variable_storage: VariableStorage):
-        super().__init__(min_value, field_type, variable_storage)
+    def __init__(self, min_value, field_type, variable_storage: VariableStorage,
+                 config_values: dict):
+        super().__init__(min_value, field_type, variable_storage, config_values)
 
     def is_met(self, response) -> bool:
         min_value = self.get_value()
@@ -121,8 +122,9 @@
 
 
 class _ConstraintMaxValue(_LoadableConstraint):
-    def __init__(self, max_value, field_type, variable_storage: VariableStorage):
-        super().__init__(max_value, field_type, variable_storage)
+    def __init__(self, max_value, field_type, variable_storage: VariableStorage,
+                 config_values: dict):
+        super().__init__(max_value, field_type, variable_storage, config_values)
 
     def is_met(self, response) -> bool:
         max_value = self.get_value()
@@ -162,16 +164,17 @@
 
 
 class _ConstraintNotValue(_LoadableConstraint):
-    def __init__(self, not_value, field_type, variable_storage: VariableStorage):
-        super().__init__(not_value, field_type, variable_storage)
+    def __init__(self, not_value, field_type, variable_storage: VariableStorage,
+                 config_values: dict):
+        super().__init__(not_value, field_type, variable_storage, config_values)
 
     def is_met(self, response) -> bool:
         not_value = self.get_value()
         return response != not_value
 
 
-def get_constraints(constraints, field_type,
-                    variable_storage: VariableStorage) -> list[BaseConstraint]:
+def get_constraints(constraints, field_type, variable_storage: VariableStorage,
+                    config_values: dict) -> list[BaseConstraint]:
     _constraints = []
     if 'hasValue' in constraints:
         _constraints.append(_ConstraintHasValue(constraints.get('hasValue')))
@@ -193,11 +196,11 @@
 
     if 'minValue' in constraints:
         _constraints.append(_ConstraintMinValue(
-            constraints.get('minValue'), field_type, variable_storage))
+            constraints.get('minValue'), field_type, variable_storage, config_values))
 
     if 'maxValue' in constraints:
         _constraints.append(_ConstraintMaxValue(
-            constraints.get('maxValue'), field_type, variable_storage))
+            constraints.get('maxValue'), field_type, variable_storage, config_values))
 
     if 'contains' in constraints:
         _constraints.append(_ConstraintContains(constraints.get('contains')))
@@ -213,6 +216,6 @@
 
     if 'notValue' in constraints:
         _constraints.append(_ConstraintNotValue(
-            constraints.get('notValue'), field_type, variable_storage))
+            constraints.get('notValue'), field_type, variable_storage, config_values))
 
     return _constraints
diff --git a/src/controller/python/chip/yaml/format_converter.py b/src/controller/python/chip/yaml/format_converter.py
index f6402c5..fc3c5a1 100644
--- a/src/controller/python/chip/yaml/format_converter.py
+++ b/src/controller/python/chip/yaml/format_converter.py
@@ -23,8 +23,44 @@
 import binascii
 
 
+def substitute_in_config_variables(field_value, config_values: dict):
+    ''' Substitutes values that are config variables.
+
+    YAML values can contain a string of a configuration variable name. In these instances we
+    substitute the configuration variable name with the actual value.
+
+    For examples see unittest src/controller/python/test/unit_tests/test_yaml_format_converter.py
+
+    # TODO This should also substitue any saveAs values as well as perform any required
+    # evaluations.
+
+    Args:
+        'field_value': Value as extracted from YAML.
+        'config_values': Dictionary of global configuration variables.
+    Returns:
+        Value with all global configuration variables substituted with the real value.
+    '''
+    if isinstance(field_value, dict):
+        return {key: substitute_in_config_variables(
+            field_value[key], config_values) for key in field_value}
+    if isinstance(field_value, list):
+        return [substitute_in_config_variables(item, config_values) for item in field_value]
+    if isinstance(field_value, str) and field_value in config_values:
+        config_value = config_values[field_value]
+        if isinstance(config_value, dict) and 'defaultValue' in config_value:
+            # TODO currently we don't validate that if config_value['type'] is provided
+            # that the type does in fact match our expectation.
+            return config_value['defaultValue']
+        return config_values[field_value]
+
+    return field_value
+
+
 def convert_yaml_octet_string_to_bytes(s: str) -> bytes:
-    """Convert YAML octet string body to bytes, handling any c-style hex escapes (e.g. \x5a) and hex: prefix"""
+    '''Convert YAML octet string body to bytes.
+
+    Included handling any c-style hex escapes (e.g. \x5a) and 'hex:' prefix.
+    '''
     # Step 1: handle explicit "hex:" prefix
     if s.startswith('hex:'):
         return binascii.unhexlify(s[4:])
@@ -60,14 +96,21 @@
     return ret_value
 
 
-def convert_yaml_type(field_value, field_type, use_from_dict=False):
-    ''' Converts yaml value to expected type.
+def convert_yaml_type(field_value, field_type, inline_cast_dict_to_struct):
+    ''' Converts yaml value to provided pythonic type.
 
-    The YAML representation when converted to a Python dictionary does not
-    quite line up in terms of type (see each of the specific if branches
-    below for the rationale for the necessary fix-ups). This function does
-    a fix-up given a field value (as present in the YAML) and its matching
-    cluster object type and returns it.
+    The YAML representation when converted to a dictionary does not line up to
+    the python type data model for the various command/attribute/event object
+    types. This function converts 'field_value' to the appropriate provided
+    'field_type'.
+
+    Args:
+        'field_value': Value as extracted from yaml
+        'field_type': Pythonic command/attribute/event object type that we
+            are converting value to.
+        'inline_cast_dict_to_struct': If true, for any dictionary 'field_value'
+            types provided we will do a convertion to the corresponding data
+            model class in `field_type` by doing field_type.FromDict(...).
     '''
     origin = typing.get_origin(field_type)
 
@@ -110,8 +153,8 @@
                     f'Did not find field "{item}" in {str(field_type)}') from None
 
             return_field_value[field_descriptor.Label] = convert_yaml_type(
-                field_value[item], field_descriptor.Type, use_from_dict)
-        if use_from_dict:
+                field_value[item], field_descriptor.Type, inline_cast_dict_to_struct)
+        if inline_cast_dict_to_struct:
             return field_type.FromDict(return_field_value)
         return return_field_value
     elif(type(field_value) is float):
@@ -122,7 +165,8 @@
 
         # The field type passed in is the type of the list element and not list[T].
         for idx, item in enumerate(field_value):
-            field_value[idx] = convert_yaml_type(item, list_element_type, use_from_dict)
+            field_value[idx] = convert_yaml_type(item, list_element_type,
+                                                 inline_cast_dict_to_struct)
         return field_value
     # YAML conversion treats all numbers as ints. Convert to a uint type if the schema
     # type indicates so.
@@ -139,3 +183,25 @@
     # By default, just return the field_value casted to field_type.
     else:
         return field_type(field_value)
+
+
+def parse_and_convert_yaml_value(field_value, field_type, config_values: dict,
+                                 inline_cast_dict_to_struct: bool = False):
+    ''' Parse and converts YAML type
+
+    Parsing the YAML value means performing required substitutions and evaluations. Parsing is
+    then followed by converting from the YAML type done using yaml.safe_load() to the type used in
+    the various command/attribute/event object data model types.
+
+    Args:
+        'field_value': Value as extracted from yaml to be parsed
+        'field_type': Pythonic command/attribute/event object type that we
+            are converting value to.
+        'config_values': Dictionary of global configuration variables.
+        'inline_cast_dict_to_struct': If true, for any dictionary 'field_value'
+            types provided we will do an inline convertion to the corresponding
+            struct in `field_type` by doing field_type.FromDict(...).
+    '''
+    field_value_with_config_variables = substitute_in_config_variables(field_value, config_values)
+    return convert_yaml_type(field_value_with_config_variables, field_type,
+                             inline_cast_dict_to_struct)
diff --git a/src/controller/python/chip/yaml/parser.py b/src/controller/python/chip/yaml/parser.py
index a3f38f7..b70a743 100644
--- a/src/controller/python/chip/yaml/parser.py
+++ b/src/controller/python/chip/yaml/parser.py
@@ -69,8 +69,8 @@
         if isinstance(value, str) and self._variable_storage.is_key_saved(value):
             self._load_expected_response_in_verify = value
         else:
-            self._expected_response = Converter.convert_yaml_type(
-                value, response_type, use_from_dict=True)
+            self._expected_response = Converter.parse_and_convert_yaml_value(
+                value, response_type, context.config_values, inline_cast_dict_to_struct=True)
 
     def verify(self, response):
         if (self._expected_response_type is None):
@@ -145,8 +145,8 @@
             request_data_as_dict = Converter.convert_name_value_pair_to_dict(args)
 
             try:
-                request_data = Converter.convert_yaml_type(
-                    request_data_as_dict, type(command_object))
+                request_data = Converter.parse_and_convert_yaml_value(
+                    request_data_as_dict, type(command_object), context.config_values)
             except ValueError:
                 raise ParsingError('Could not covert yaml type')
 
@@ -166,8 +166,8 @@
             expected_response_args = self._expected_raw_response['values']
             expected_response_data_as_dict = Converter.convert_name_value_pair_to_dict(
                 expected_response_args)
-            expected_response_data = Converter.convert_yaml_type(
-                expected_response_data_as_dict, expected_command)
+            expected_response_data = Converter.parse_and_convert_yaml_value(
+                expected_response_data_as_dict, expected_command, context.config_values)
             self._expected_response_object = expected_command.FromDict(expected_response_data)
 
     def run_action(self, dev_ctrl: ChipDeviceCtrl, endpoint: int, node_id: int):
@@ -260,7 +260,8 @@
         if constraints:
             self._constraints = get_constraints(constraints,
                                                 self._request_object.attribute_type.Type,
-                                                context.variable_storage)
+                                                context.variable_storage,
+                                                context.config_values)
 
     def run_action(self, dev_ctrl: ChipDeviceCtrl, endpoint: int, node_id: int):
         try:
@@ -326,8 +327,8 @@
         if (item.get('arguments')):
             args = item['arguments']['value']
             try:
-                request_data = Converter.convert_yaml_type(
-                    args, attribute.attribute_type.Type)
+                request_data = Converter.parse_and_convert_yaml_value(
+                    args, attribute.attribute_type.Type, context.config_values)
             except ValueError:
                 raise ParsingError('Could not covert yaml type')
 
diff --git a/src/controller/python/test/unit_tests/test_yaml_format_converter.py b/src/controller/python/test/unit_tests/test_yaml_format_converter.py
index fa46705..05f58d2 100644
--- a/src/controller/python/test/unit_tests/test_yaml_format_converter.py
+++ b/src/controller/python/test/unit_tests/test_yaml_format_converter.py
@@ -15,7 +15,7 @@
 #    limitations under the License.
 #
 
-from chip.yaml.format_converter import convert_yaml_octet_string_to_bytes
+from chip.yaml.format_converter import convert_yaml_octet_string_to_bytes, substitute_in_config_variables
 from binascii import unhexlify
 import unittest
 
@@ -44,6 +44,75 @@
             convert_yaml_octet_string_to_bytes("hex:aa5")
 
 
+class TestSubstitueInConfigVariables(unittest.TestCase):
+
+    def setUp(self):
+        self.common_config = {
+            'arg1': {
+                'defaultValue': 1
+            },
+            'arg2': {
+                'defaultValue': 2
+            },
+            'no_explicit_default': 3
+        }
+
+    def test_basic_substitution(self):
+        self.assertEqual(substitute_in_config_variables('arg1', self.common_config), 1)
+        self.assertEqual(substitute_in_config_variables('arg2', self.common_config), 2)
+        self.assertEqual(substitute_in_config_variables('arg3', self.common_config), 'arg3')
+        self.assertEqual(substitute_in_config_variables('no_explicit_default', self.common_config), 3)
+
+    def test_basis_dict_substitution(self):
+        basic_dict = {
+            'arg1': 'arg1',
+            'arg2': 'arg2',
+            'arg3': 'arg3',
+            'no_explicit_default': 'no_explicit_default',
+        }
+        expected_dict = {
+            'arg1': 1,
+            'arg2': 2,
+            'arg3': 'arg3',
+            'no_explicit_default': 3,
+        }
+        self.assertEqual(substitute_in_config_variables(basic_dict, self.common_config), expected_dict)
+
+    def test_basis_list_substitution(self):
+        basic_list = ['arg1', 'arg2', 'arg3', 'no_explicit_default']
+        expected_list = [1, 2, 'arg3', 3]
+        self.assertEqual(substitute_in_config_variables(basic_list, self.common_config), expected_list)
+
+    def test_complex_nested_type(self):
+        complex_nested_type = {
+            'arg1': ['arg1', 'arg2', 'arg3', 'no_explicit_default'],
+            'arg2': 'arg22',
+            'arg3': {
+                'no_explicit_default': 'no_explicit_default',
+                'arg2': 'arg2',
+                'another_dict': {
+                    'arg1': ['arg1', 'arg1', 'arg1', 'no_explicit_default'],
+                },
+                'another_list': ['arg1', 'arg2', 'arg3', 'no_explicit_default']
+            },
+            'no_explicit_default': 'no_explicit_default',
+        }
+        expected_result = {
+            'arg1': [1, 2, 'arg3', 3],
+            'arg2': 'arg22',
+            'arg3': {
+                'no_explicit_default': 3,
+                'arg2': 2,
+                'another_dict': {
+                    'arg1': [1, 1, 1, 3],
+                },
+                'another_list': [1, 2, 'arg3', 3]
+            },
+            'no_explicit_default': 3,
+        }
+        self.assertEqual(substitute_in_config_variables(complex_nested_type, self.common_config), expected_result)
+
+
 def main():
     unittest.main()