Giovinazzo was born and raised in Staten Island, New York, the son of Nancy and Dominick Giovinazzo. Growing up on Staten Island, 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, so, with the support of his family, he turned to acting. He studied acting at Wagner College and HB Studios, and spent 4 years working mostly non-paying roles around the NYC area "making his bones."
In 1997, Giovinazzo moved to Los Angeles. Not long afterward, he successfully landed his first Hollywood role in the Buffy the Vampire Slayer pilot, 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. 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 "Columbo Likes the Nightlife", the final episode of the TV series Columbo.
Giovinazzo was cast as forensic scientist Danny Messer on the hit TV series CSI: NY and is the first actor to appear in all three CSI series; his CSI: NY character was introduced in the CSI: Miami episode "MIA/NYC NonStop" (along with the other cast members of CSI: NY), and he guest-starred in the third season of the original, Las Vegas-based CSI: Crime Scene Investigation as a street racer named Thumpy G, in the episode "Revenge is Best Served Cold", though it is never specified that this guest spot was in any way related to his character on CSI: NY. Giovinazzo penned the sixth season vampire-themed episode "Sanguine Love", joining series leads Melina Kanakaredes and Gary Sinise, who have also written episodes for the series.
Starting from 2014, Giovinazzo began portraying the recurring role of Sid Markham in the second season of the USA television series Graceland. In this series, he reunited with his former CSI: NY co-star, Vanessa Ferlito.
Giovinazzo plays the guitar, and writes songs and poetry. He is also a painter, mostly in oils, and one of his paintings appeared in the "Tri-Borough" episode of CSI: NY. He is currently a lead vocalist in his band Ceesau, which released one album, Era of the Exposed (2008), with five songs. The song "Tear To Spare", from his album, was played in the CSI: NY sixth season episode "Sanguine Love", which Giovinazzo wrote.
He is a cousin of Vincent Giovinazzo, Buddy Giovinazzo, Michael "Big Mean Schkeen" Giovinazzo, Rick Giovinazzo, and Larry Romano's, and has a dog named Enzo.
Giovinazzo married actress Vanessa Marcil on July 11, 2010, in a private ceremony in New York City In June 2011, the couple announced they were expecting their first child together; however, Marcil suffered a miscarriage, her second that year. Marcil filed for divorce in August 2012 on the basis of irreconcilable differences. The divorce was finalized in March 2013.
|1996||No Way Home||Frankie Hamm||Film|
|1997||Buffy the Vampire Slayer||Christopher Boal||Episode 1.01 "Welcome to the Hellmouth"|
|1997||Pacific Blue||Cody Fisher||Episode 3.08 "Matters of the Heart"|
|1998||Fallen Arches||Frankie Romano||Film|
|1998||Billy's Hollywood Screen Kiss||Gundy||Film|
|1999||The Big Brass Ring||Young Billy||Film|
|1999||Providence||Kit||Episode 1.17 "Heaven Can Wait"|
|2001||The Learning Curve||Paul Cleveland||Film|
|1999||For Love of the Game||Ken Strout||Film|
|1999||Shasta McNasty||Scott||All 22 episodes|
|2000||Terror Tract||Frank Sarno||Film ("Nightmare" segment)|
|2001||Black Hawk Down||Goodale||Film|
|2002||Big Shot: Confessions of a Campus Bookie||T-Bone||TV movie|
|2002||CSI: Crime Scene Investigation||Thumpy G||Episode 3.01 "Revenge is Best Served Cold"|
|2003||Columbo||Tony Galper||Episode 13.05 "Columbo Likes the Nightlife"|
|2004||In Enemy Hands||Buck Cooper||Film|
|2004||CSI: Miami||Danny Messer||Episode 2.23 "MIA/NYC NonStop"|
|2004–13||CSI: NY||Danny Messer||All 197 episodes|
|2008||This Is Not a Test||Trey||Film|
|2014–15||Graceland||Sid Markham||9 episodes (2.06–3.02)|
|2015||The Player||Ray||Episode 1.04 "The Big Blind"|
|2016||Criminal Minds||Andrew Meeks||Episode 11.15 "A Badge and a Gun"|