Gus Halper (born 2 July 1992, Manhattan, New York City) is an American film, television, and stage actor. His mother, Deann Simmons Halper, is an actress and theatre director. He graduated from the University of North Carolina School of the Arts in 2014, where he played Romeo in the school's production of Romeo and Juliet. On stage, he was nominated for a Lucille Lortel Award for Ride the Cyclone (2016) and won the Outer Critics Circle Award for Outstanding Featured Actor in a Musical for Sing Street (2019–20). He married actress Emma Geer in October 2023; their first child was born in early 2026. His most notable screen roles include Erik Menendez in Law & Order True Crime: The Menendez Murders (2017) (Edie Falco, John Turturro), Bone in Cold Pursuit (2019) (Liam Neeson, Toni Collette), Joseph Lyman in Dickinson (2019) (Hailee Steinfeld, Danny Ramirez), Tom Kahn in Rustin (2023) (Colman Domingo, Jeffrey Wright), and Mr. C in Unabomber (2026) (Russell Crowe, Jacob Tremblay). He also appeared in Ricki and the Flash (2015) (Meryl Streep, Kevin Kline) and Fear the Walking Dead (2021) (Kim Dickens, Lennie James).