Gabriel Mangiante is currently the director of Information Services for the Signature Theatre in which he was also a music director for in previous years. During his time as music director, Mangiante held an important role in a long list of accomplishments, including: The Threepenny Opera, BeachesCrossingMiss SaigonSpinCompany; Hello, Dolly! (Ford’s Theatre co-production); Shakespeare's R&J (composer); DreamgirlsThe Best Little Whorehouse in Texas; XanaduBrother Russia; Hairspray; Sweet Tea; The Hollow; The Boy Detective Fails; Side By Side By SondheimAnd The Curtain RisesSunset BoulevardChessDirty Blonde; Partial EclipseGiant; numerous cabarets, concerts, and workshops.

Before his time with the Signature Theatre, Mangiante was on the staff of Catholic University, and was also the music director for Side Show at the Theatre Lab in Washington, D.C. Other credits include Reefer Madness (Helen Hayes Award for Outstanding Resident Musical) and This Beautiful City at the Studio Theatre.