Brennan hails from the San Francisco Bay Area, where he grew up training with A.C.T., Berkeley Rep, Marin Theater Company, and more.
He graduated with honors from New York University's Tisch School of the Arts, where he earned a BFA in Drama and trained at the Stella Adler Studio of Acting. He enjoyed performing in the New York International Fringe Festival and with the Phoenix Theater Ensemble. He also wrote, produced, and directed a one-act comedy, God's Last Day, which won Best Short Play in the 2015 Unchained Theater Festival.
After returning to San Francisco, Brennan has performed with the Cutting Ball Theater, Marin Shakespeare Company, New Conservatory Theatre Center, Stanford Repertory Theatre, Faultline Theater, Boxcar Theater, and The Playwrights Foundation.
Brennan is an EMC candidate and is represented by NYLO Talent Agency.