Zayas joined the United States Air Force at age 19 and was a police officer with the New York City Police Department for almost 15 years. His experience as a police officer allowed him to develop as a character actor, leading to a series of acting jobs on television and film, mainly playing law enforcement officers, but playing characters on the other side of the law, as well, such as Enrique Morales on HBO's long-running prison-drama Oz (2000-2003) and Osborne the cop in Rounders (1998).
Zayas has been a member of the LAByrinth Theater Company since 1992, a New York City-based traveling actors group. He branched out into television and film projects, and has diversified with guest roles in such popular television series such as New York Undercover, Person of Interest, and NYPD Blue. At LAByrinth, he met his future wife, actress Liza Colón.Zayas played a corrupt police officer in 16 Blocks (2006) and an NYPD officer in Michael Clayton (2007). He is featured in the independent film Shadowboxing (2010), which appeared on the film festival circuit. He appears in Sylvester Stallone's feature film The Expendables (2010) and The Brothers Strause's film Skyline (2010). In 2012, Zayas played Ernie Trask, a hotel super, in the twelfth episode of season 1 of Person of Interest. Zayas appeared in an episode of Fox's drama The Following, playing the part of Tyson, Ryan Hardy's (retired) FBI best friend. He portrays mob boss Don Salvatore Maroni in the Batman prequel, Gotham, which premiered on Fox on September 22, 2014. Shortly thereafter, he appeared in Annie (2014) as Lou, a gregarious bodega owner who helps Cameron Diaz's Hannigan learn to love herself.