Friends, where he had a recurring role as Phoebe's cute, naive younger brother Frank (1995-2003). He has a relationship with his much older female teacher, and later asks Phoebe to be the surrogate mother for his children.
But the 21-year old actor was a busy child star under the name Vonnie Ribisi, with recurring roles in The New Leave It to Beaver, My Two Dads, The Wonder Years, and Family Album; below he stars in the nuclear family sitcom Davis Rules (1991-92), along with Luke Edwards and Nathan Watt.
As a young adult, his lean, rugged frame and handsome but quirky face did not gain him a lot of mainstream blockbuster roles, but he made a splash in independent films:
SubUrbia (1996): a group of teens in small-town Austin, Texas (of all places) experience angst and want to escape. Notable for Giovanni's first nude scene.
Lost Highway (1997): I have no idea what it's about.
Scotch and Milk (1998): Notable for starring both Giovanni Ribisi and his lookalike Adam Goldberg.
And his resume goes on like that, movie after movie that few people outside the art house circuit have seen, with an occasional mainstream title: Gone in Sixty Seconds, Avatar.
And pitiably few tv roles. Chiefly My Name is Earl (2005-2008), where he played Ralph Mariano, an old buddy of Earl's who reappears and asks him to resume his life of crime. They have a combative relationship with the implication of previous homoerotic activity. (And he appears in his underwear).
In 2013-2014 he starred in the execrable Dads (2013-14), which I saw only half an episode of. That was enough.
I get such a strong gay vibe from Giovanni that I expected a lot of gay characters or subtexts in his work. It is astonishing that there really isn't much, just the obnoxious gay soldier Levi Kendall in Basic (2003) and creepy Donny who kidnaps the talking teddy bear in the execrable Ted (2012).
But he's apparently heterosexual in real life. And he may even be a homophobe of the Seth Green "No way am I gay!!!!" school.