He has served as conductor/assistant conductor/pianist for over 180 operatic productions with 33 companies, including Opera Theatre of St. Louis, Boston Lyric Opera, Boston Symphony Orchestra, Boston Youth Symphony Orchestra, Wolf Trap Opera, Central City Opera, and Opera Maine. He assisted with the Pulitzer Prize-winning opera Madame White Snake for workshops and productions in Boston and Taiwan and as a part of the Ouroboros Trilogy in 2016. He has premiered numerous operas and song cycles as conductor and pianist, including works by Dominick Argento, Scott Wheeler, Elena Ruehr, Francine Trester, Enrico Garzilli, and Thomas Oboe Lee.

As an audition pianist he has played for thousands of opera auditions and competitions throughout the country, and in concerts he has collaborated with hundreds of singers, instrumentalists, and choirs. He has assisted as recording producer for award-winning recordings by the Florestan Recital Project and Cappella Clausula. An extremely active vocal coach, Timothy has worked with both young singers and seasoned professionals, including Denyce Graves, Bryn Terfel, and James Maddelena.

Currently he is the music director for the Studio Artists program at Opera Maine, the producer of Milton Community Concerts, and the organist/music director at historic First Parish Church in Milton, Mass. In Boston he has performed with Emmanuel Music (where he played for a decade of weekly Bach cantata rehearsals), the Handel and Haydn Society, and the Commonwealth Shakespeare Company, among others.