Tamzarian was previously a partner of the law firm of Case, Knowlson, Jordan & Wright LLP, now known as Case, Knowlson & Jordan LLP. He has previously served as a Judge Pro Tem of the Los Angeles County Superior Court (LACSC) and a research attorney at LACSC. In private practice, Tamzarian specialized in business and real estate litigation in both state and federal court. He has been a longtime Armenian American community activist in both Massachusetts and California volunteering with the Armenian General Benevolent Union as well as the Armenian National Committee of Glendale.