diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index aebe1b2371..6fad108dab 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -112,6 +112,7 @@ Fixed
   Contributed by Tatsuma Matsuki (@mtatsuma)
 
 * Fix dependency conflicts by updating ``requests`` (2.23.0) and ``gitpython`` (2.1.15). #4869
+* Fixed serializing array parameters (bug fix) #4804, #4861, #4872
 
 3.1.0 - June 27, 2019
 ---------------------
diff --git a/st2common/st2common/util/action_db.py b/st2common/st2common/util/action_db.py
index 39e137c559..a69c16bd3c 100644
--- a/st2common/st2common/util/action_db.py
+++ b/st2common/st2common/util/action_db.py
@@ -283,9 +283,9 @@ def serialize_positional_argument(argument_type, argument_value):
             argument_value = '1' if bool(argument_value) else '0'
         else:
             argument_value = ''
-    elif argument_type == 'list':
+    elif argument_type in ['array', 'list']:
         # Lists are serialized a comma delimited string (foo,bar,baz)
-        argument_value = ','.join(argument_value) if argument_value else ''
+        argument_value = ','.join(map(str, argument_value)) if argument_value else ''
     elif argument_type == 'object':
         # Objects are serialized as JSON
         argument_value = json.dumps(argument_value) if argument_value else ''
diff --git a/st2common/tests/unit/test_action_db_utils.py b/st2common/tests/unit/test_action_db_utils.py
index 68ee865596..737b9a7c6c 100644
--- a/st2common/tests/unit/test_action_db_utils.py
+++ b/st2common/tests/unit/test_action_db_utils.py
@@ -327,7 +327,7 @@ def test_get_args(self):
             'runnerint': 555
         }
         pos_args, named_args = action_db_utils.get_args(params, ActionDBUtilsTestCase.action_db)
-        self.assertListEqual(pos_args, ['20', '', 'foo', '', '', '', ''],
+        self.assertListEqual(pos_args, ['20', '', 'foo', '', '', '', '', ''],
                             'Positional args not parsed correctly.')
         self.assertNotIn('actionint', named_args)
         self.assertNotIn('actionstr', named_args)
@@ -340,6 +340,7 @@ def test_get_args(self):
             'actionfloat': 1.5,
             'actionstr': 'string value',
             'actionbool': True,
+            'actionarray': ['foo', 'bar', 'baz', 'qux'],
             'actionlist': ['foo', 'bar', 'baz'],
             'actionobject': {'a': 1, 'b': '2'},
         }
@@ -348,6 +349,7 @@ def test_get_args(self):
             '1.5',
             'string value',
             '1',
+            'foo,bar,baz,qux',
             'foo,bar,baz',
             '{"a": 1, "b": "2"}',
             ''
@@ -361,6 +363,7 @@ def test_get_args(self):
             'actionfloat': 1.5,
             'actionstr': 'string value',
             'actionbool': False,
+            'actionarray': [],
             'actionlist': [],
             'actionobject': {'a': 1, 'b': '2'},
         }
@@ -370,6 +373,7 @@ def test_get_args(self):
             'string value',
             '0',
             '',
+            '',
             '{"a": 1, "b": "2"}',
             ''
         ]
@@ -383,6 +387,7 @@ def test_get_args(self):
             'actionfloat': None,
             'actionstr': None,
             'actionbool': None,
+            'actionarray': None,
             'actionlist': None,
             'actionobject': None,
         }
@@ -393,6 +398,7 @@ def test_get_args(self):
             '',
             '',
             '',
+            '',
             ''
         ]
         pos_args, _ = action_db_utils.get_args(params, ActionDBUtilsTestCase.action_db)
@@ -412,6 +418,7 @@ def test_get_args(self):
             '',
             '',
             '',
+            '',
             ''
         ]
         pos_args, named_args = action_db_utils.get_args(params, ActionDBUtilsTestCase.action_db)
@@ -463,9 +470,10 @@ def setup_action_models(cls):
             'actionfloat': {'type': 'float', 'required': False, 'position': 1},
             'actionstr': {'type': 'string', 'required': True, 'position': 2},
             'actionbool': {'type': 'boolean', 'required': False, 'position': 3},
-            'actionlist': {'type': 'list', 'required': False, 'position': 4},
-            'actionobject': {'type': 'object', 'required': False, 'position': 5},
-            'actionnull': {'type': 'null', 'required': False, 'position': 6},
+            'actionarray': {'type': 'array', 'required': False, 'position': 4},
+            'actionlist': {'type': 'list', 'required': False, 'position': 5},
+            'actionobject': {'type': 'object', 'required': False, 'position': 6},
+            'actionnull': {'type': 'null', 'required': False, 'position': 7},
 
             'runnerdummy': {'type': 'string', 'default': 'actiondummy'}
         }