diff --git a/packages/kbn-esql-ast/src/builder/builder.ts b/packages/kbn-esql-ast/src/builder/builder.ts
index d033e177bd4b5..894ab99e5b3e8 100644
--- a/packages/kbn-esql-ast/src/builder/builder.ts
+++ b/packages/kbn-esql-ast/src/builder/builder.ts
@@ -18,10 +18,14 @@ import {
   ESQLCommand,
   ESQLCommandOption,
   ESQLDecimalLiteral,
+  ESQLIdentifier,
   ESQLInlineCast,
   ESQLIntegerLiteral,
   ESQLList,
   ESQLLocation,
+  ESQLNamedParamLiteral,
+  ESQLParam,
+  ESQLPositionalParamLiteral,
   ESQLOrderExpression,
   ESQLSource,
 } from '../types';
@@ -190,4 +194,65 @@ export namespace Builder {
       };
     }
   }
+
+  export const identifier = (
+    template: AstNodeTemplate<ESQLIdentifier>,
+    fromParser?: Partial<AstNodeParserFields>
+  ): ESQLIdentifier => {
+    return {
+      ...template,
+      ...Builder.parserFields(fromParser),
+      type: 'identifier',
+    };
+  };
+
+  export namespace param {
+    export const unnamed = (fromParser?: Partial<AstNodeParserFields>): ESQLParam => {
+      const node = {
+        ...Builder.parserFields(fromParser),
+        name: '',
+        value: '',
+        paramType: 'unnamed',
+        type: 'literal',
+        literalType: 'param',
+      };
+
+      return node as ESQLParam;
+    };
+
+    export const named = (
+      template: Omit<AstNodeTemplate<ESQLNamedParamLiteral>, 'name' | 'literalType' | 'paramType'>,
+      fromParser?: Partial<AstNodeParserFields>
+    ): ESQLNamedParamLiteral => {
+      const node: ESQLNamedParamLiteral = {
+        ...template,
+        ...Builder.parserFields(fromParser),
+        name: '',
+        type: 'literal',
+        literalType: 'param',
+        paramType: 'named',
+      };
+
+      return node;
+    };
+
+    export const positional = (
+      template: Omit<
+        AstNodeTemplate<ESQLPositionalParamLiteral>,
+        'name' | 'literalType' | 'paramType'
+      >,
+      fromParser?: Partial<AstNodeParserFields>
+    ): ESQLPositionalParamLiteral => {
+      const node: ESQLPositionalParamLiteral = {
+        ...template,
+        ...Builder.parserFields(fromParser),
+        name: '',
+        type: 'literal',
+        literalType: 'param',
+        paramType: 'positional',
+      };
+
+      return node;
+    };
+  }
 }
diff --git a/packages/kbn-esql-ast/src/parser/__tests__/function.test.ts b/packages/kbn-esql-ast/src/parser/__tests__/function.test.ts
index 9d822f78f9333..d05ed36204b17 100644
--- a/packages/kbn-esql-ast/src/parser/__tests__/function.test.ts
+++ b/packages/kbn-esql-ast/src/parser/__tests__/function.test.ts
@@ -69,6 +69,103 @@ describe('function AST nodes', () => {
         },
       ]);
     });
+
+    it('parses out function name as identifier node', () => {
+      const query = 'ROW fn(1, 2, 3)';
+      const { ast, errors } = parse(query);
+
+      expect(errors.length).toBe(0);
+      expect(ast).toMatchObject([
+        {
+          type: 'command',
+          name: 'row',
+          args: [
+            {
+              type: 'function',
+              name: 'fn',
+              operator: {
+                type: 'identifier',
+                name: 'fn',
+              },
+            },
+          ],
+        },
+      ]);
+    });
+
+    it('parses out function name as named param', () => {
+      const query = 'ROW ?insert_here(1, 2, 3)';
+      const { ast, errors } = parse(query);
+
+      expect(errors.length).toBe(0);
+      expect(ast).toMatchObject([
+        {
+          type: 'command',
+          name: 'row',
+          args: [
+            {
+              type: 'function',
+              name: '?insert_here',
+              operator: {
+                type: 'literal',
+                literalType: 'param',
+                paramType: 'named',
+                value: 'insert_here',
+              },
+            },
+          ],
+        },
+      ]);
+    });
+
+    it('parses out function name as unnamed param', () => {
+      const query = 'ROW ?(1, 2, 3)';
+      const { ast, errors } = parse(query);
+
+      expect(errors.length).toBe(0);
+      expect(ast).toMatchObject([
+        {
+          type: 'command',
+          name: 'row',
+          args: [
+            {
+              type: 'function',
+              name: '?',
+              operator: {
+                type: 'literal',
+                literalType: 'param',
+                paramType: 'unnamed',
+              },
+            },
+          ],
+        },
+      ]);
+    });
+
+    it('parses out function name as positional param', () => {
+      const query = 'ROW ?30035(1, 2, 3)';
+      const { ast, errors } = parse(query);
+
+      expect(errors.length).toBe(0);
+      expect(ast).toMatchObject([
+        {
+          type: 'command',
+          name: 'row',
+          args: [
+            {
+              type: 'function',
+              name: '?30035',
+              operator: {
+                type: 'literal',
+                literalType: 'param',
+                paramType: 'positional',
+                value: 30035,
+              },
+            },
+          ],
+        },
+      ]);
+    });
   });
 
   describe('"unary-expression"', () => {
diff --git a/packages/kbn-esql-ast/src/parser/factories.ts b/packages/kbn-esql-ast/src/parser/factories.ts
index 246a62747ee6e..b575447f7e744 100644
--- a/packages/kbn-esql-ast/src/parser/factories.ts
+++ b/packages/kbn-esql-ast/src/parser/factories.ts
@@ -11,7 +11,13 @@
  * In case of changes in the grammar, this script should be updated: esql_update_ast_script.js
  */
 
-import type { Token, ParserRuleContext, TerminalNode, RecognitionException } from 'antlr4';
+import type {
+  Token,
+  ParserRuleContext,
+  TerminalNode,
+  RecognitionException,
+  ParseTree,
+} from 'antlr4';
 import {
   IndexPatternContext,
   QualifiedNameContext,
@@ -21,6 +27,10 @@ import {
   type IntegerValueContext,
   type QualifiedIntegerLiteralContext,
   QualifiedNamePatternContext,
+  FunctionContext,
+  IdentifierContext,
+  InputParamContext,
+  InputNamedOrPositionalParamContext,
 } from '../antlr/esql_parser';
 import { DOUBLE_TICKS_REGEX, SINGLE_BACKTICK, TICKS_REGEX } from './constants';
 import type {
@@ -42,6 +52,8 @@ import type {
   ESQLNumericLiteral,
   ESQLOrderExpression,
   InlineCastingType,
+  ESQLFunctionCallExpression,
+  ESQLIdentifier,
 } from '../types';
 import { parseIdentifier, getPosition } from './helpers';
 import { Builder, type AstNodeParserFields } from '../builder';
@@ -201,6 +213,60 @@ export function createFunction<Subtype extends FunctionSubtype>(
   return node;
 }
 
+export const createFunctionCall = (ctx: FunctionContext): ESQLFunctionCallExpression => {
+  const functionExpressionCtx = ctx.functionExpression();
+  const functionName = functionExpressionCtx.functionName();
+  const node: ESQLFunctionCallExpression = {
+    type: 'function',
+    subtype: 'variadic-call',
+    name: functionName.getText().toLowerCase(),
+    text: ctx.getText(),
+    location: getPosition(ctx.start, ctx.stop),
+    args: [],
+    incomplete: Boolean(ctx.exception),
+  };
+
+  const identifierOrParameter = functionName.identifierOrParameter();
+  if (identifierOrParameter) {
+    const identifier = identifierOrParameter.identifier();
+    if (identifier) {
+      node.operator = createIdentifier(identifier);
+    } else {
+      const parameter = identifierOrParameter.parameter();
+      if (parameter) {
+        node.operator = createParam(parameter);
+      }
+    }
+  }
+
+  return node;
+};
+
+const createIdentifier = (identifier: IdentifierContext): ESQLIdentifier => {
+  return Builder.identifier(
+    { name: identifier.getText().toLowerCase() },
+    createParserFields(identifier)
+  );
+};
+
+export const createParam = (ctx: ParseTree) => {
+  if (ctx instanceof InputParamContext) {
+    return Builder.param.unnamed(createParserFields(ctx));
+  } else if (ctx instanceof InputNamedOrPositionalParamContext) {
+    const text = ctx.getText();
+    const value = text.slice(1);
+    const valueAsNumber = Number(value);
+    const isPositional = String(valueAsNumber) === value;
+    const parserFields = createParserFields(ctx);
+
+    if (isPositional) {
+      return Builder.param.positional({ value: valueAsNumber }, parserFields);
+    } else {
+      return Builder.param.named({ value }, parserFields);
+    }
+  }
+};
+
 export const createOrderExpression = (
   ctx: ParserRuleContext,
   arg: ESQLColumn,
diff --git a/packages/kbn-esql-ast/src/parser/walkers.ts b/packages/kbn-esql-ast/src/parser/walkers.ts
index 268c90417078b..60d69a17bb1c7 100644
--- a/packages/kbn-esql-ast/src/parser/walkers.ts
+++ b/packages/kbn-esql-ast/src/parser/walkers.ts
@@ -60,8 +60,6 @@ import {
   type ValueExpressionContext,
   ValueExpressionDefaultContext,
   InlineCastContext,
-  InputNamedOrPositionalParamContext,
-  InputParamContext,
   IndexPatternContext,
   InlinestatsCommandContext,
 } from '../antlr/esql_parser';
@@ -86,8 +84,9 @@ import {
   createInlineCast,
   createUnknownItem,
   createOrderExpression,
+  createFunctionCall,
+  createParam,
 } from './factories';
-import { getPosition } from './helpers';
 
 import {
   ESQLLiteral,
@@ -97,9 +96,6 @@ import {
   ESQLAstItem,
   ESQLAstField,
   ESQLInlineCast,
-  ESQLUnnamedParamLiteral,
-  ESQLPositionalParamLiteral,
-  ESQLNamedParamLiteral,
   ESQLOrderExpression,
 } from '../types';
 import { firstItem, lastItem } from '../visitor/utils';
@@ -390,50 +386,8 @@ function getConstant(ctx: ConstantContext): ESQLAstItem {
     const values: ESQLLiteral[] = [];
 
     for (const child of ctx.children) {
-      if (child instanceof InputParamContext) {
-        const literal: ESQLUnnamedParamLiteral = {
-          type: 'literal',
-          literalType: 'param',
-          paramType: 'unnamed',
-          text: ctx.getText(),
-          name: '',
-          value: '',
-          location: getPosition(ctx.start, ctx.stop),
-          incomplete: Boolean(ctx.exception),
-        };
-        values.push(literal);
-      } else if (child instanceof InputNamedOrPositionalParamContext) {
-        const text = child.getText();
-        const value = text.slice(1);
-        const valueAsNumber = Number(value);
-        const isPositional = String(valueAsNumber) === value;
-
-        if (isPositional) {
-          const literal: ESQLPositionalParamLiteral = {
-            type: 'literal',
-            literalType: 'param',
-            paramType: 'positional',
-            value: valueAsNumber,
-            text,
-            name: '',
-            location: getPosition(ctx.start, ctx.stop),
-            incomplete: Boolean(ctx.exception),
-          };
-          values.push(literal);
-        } else {
-          const literal: ESQLNamedParamLiteral = {
-            type: 'literal',
-            literalType: 'param',
-            paramType: 'named',
-            value,
-            text,
-            name: '',
-            location: getPosition(ctx.start, ctx.stop),
-            incomplete: Boolean(ctx.exception),
-          };
-          values.push(literal);
-        }
-      }
+      const param = createParam(child);
+      if (param) values.push(param);
     }
 
     return values;
@@ -478,15 +432,7 @@ export function visitPrimaryExpression(ctx: PrimaryExpressionContext): ESQLAstIt
   }
   if (ctx instanceof FunctionContext) {
     const functionExpressionCtx = ctx.functionExpression();
-    const functionNameContext = functionExpressionCtx.functionName().MATCH()
-      ? functionExpressionCtx.functionName().MATCH()
-      : functionExpressionCtx.functionName().identifierOrParameter();
-    const fn = createFunction(
-      functionNameContext.getText().toLowerCase(),
-      ctx,
-      undefined,
-      'variadic-call'
-    );
+    const fn = createFunctionCall(ctx);
     const asteriskArg = functionExpressionCtx.ASTERISK()
       ? createColumnStar(functionExpressionCtx.ASTERISK()!)
       : undefined;
diff --git a/packages/kbn-esql-ast/src/types.ts b/packages/kbn-esql-ast/src/types.ts
index eabdefa5a401a..ea76fc3e0b9a4 100644
--- a/packages/kbn-esql-ast/src/types.ts
+++ b/packages/kbn-esql-ast/src/types.ts
@@ -26,6 +26,7 @@ export type ESQLSingleAstItem =
   | ESQLTimeInterval
   | ESQLList
   | ESQLLiteral
+  | ESQLIdentifier
   | ESQLCommandMode
   | ESQLInlineCast
   | ESQLOrderExpression
@@ -132,6 +133,11 @@ export interface ESQLFunction<
    */
   subtype?: Subtype;
 
+  /**
+   * A node representing the function or operator being called.
+   */
+  operator?: ESQLIdentifier | ESQLParamLiteral;
+
   args: ESQLAstItem[];
 }
 
@@ -363,6 +369,10 @@ export interface ESQLNamedParamLiteral extends ESQLParamLiteral<'named'> {
   value: string;
 }
 
+export interface ESQLIdentifier extends ESQLAstBaseItem {
+  type: 'identifier';
+}
+
 export const isESQLNamedParamLiteral = (node: ESQLAstItem): node is ESQLNamedParamLiteral =>
   isESQLAstBaseItem(node) &&
   (node as ESQLNamedParamLiteral).literalType === 'param' &&
@@ -376,6 +386,11 @@ export interface ESQLPositionalParamLiteral extends ESQLParamLiteral<'positional
   value: number;
 }
 
+export type ESQLParam =
+  | ESQLUnnamedParamLiteral
+  | ESQLNamedParamLiteral
+  | ESQLPositionalParamLiteral;
+
 export interface ESQLMessage {
   type: 'error' | 'warning';
   text: string;