Giovinazzo was born and raised in the Port Richmond neighborhood of Staten Island, New York, the son of Nancy and Dominick Giovinazzo. Growing up, Giovinazzo was an avid athlete. He graduated from Port Richmond High School in 1991 and attended Wagner College on a baseball scholarship. He had hoped to become a professional baseball player, but a serious back injury dashed his career plans; with the support of his family, he turned to acting. He studied acting at Wagner College and HB Studios, and spent four years working mostly non-paying roles in the New York area.

In 1997, Giovinazzo moved to Los Angeles. Not long afterward, he successfully landed his first Hollywood role in the pilot of Buffy the Vampire Slayer, in which his character was the show’s first on-screen victim. Afterwards, he appeared in numerous guest-starring roles on television and in film, including Billy’s Hollywood Screen Kiss, For Love of the Game, The Big Brass Ring, and Black Hawk Down. He was also cast as one of the stars of the short-lived UPN sitcom Shasta McNasty, which was nominated for a Peoples Choice Award. Other films in which he had starring roles include In Enemy Hands with William H. Macy, and Players with Freddy Rodriguez and Peter Dobson. He played Tony Galper, the victim in the final episode of the TV series Columbo.

Giovinazzo married actress Vanessa Marcil on July 11, 2010, in a private ceremony in New York City. Marcil filed for divorce in August 2012 on the basis of irreconcilable differences. The divorce was finalized in March 2013.

In 2014, Giovinazzo portrayed the recurring role of Sid Markham in season two of the USA television series Graceland. In this series, he reunited with his former CSI: NY co-star Vanessa Ferlito.