Stewart founded Stewart L. Mueller, CPA in 1998 and has been a QuickBooks Certified ProAdvisor since the program's inception in 1999. He has trained and consulted clients in the use of QuickBooks accounting software since 1992. He is a charter member of the Intuit Solution Provider Program which is a program Intuit uses to sell, implement and train QuickBooks software for mid-market companies. Stewart was a participant in the Accountant and Advisor Customer Council for Intuit Inc. from 2005-2007. While participating on the Council, he provided input and feedback to Intuit's management and product development engineers. Stewart began the first 10 years of his career in private industry. He has been in public accounting and has worked with clients ranging in size from $100k to $60m+ in annual revenues, providing controllership, tax compliance/advisory services, systems set up and consultations.