A New Jersey native, Hegyes studied speech and theater at Rowan University (where he taught later in his career) before finding stage work in New York both on and off Broadway. In 1975, Hegyes was cast on Welcome Back, Kotter as one of the Sweathogs alongside a young John Travolta. After the comedy's four-year run, Hegyes joined the detective series Cagney & Lacey as undercover detective Manny Esposito.
More recently, Hegyes guest-starred on shows like NewsRadio, Diagnosis Murder and The Drew Carey Show. Health problems in the past several years, including a heart attack, kept him out of the limelight. However, he did reunite with the rest of the Welcome Back, Kotter cast at last year's TV Land Awards.
Hegyes is survived by three siblings, two children, Cassie and Mac, and two stepchildren, Sophia and Alex.