The 28-year-old has agreed a two-year contract with the Tigers after being released by Manchester City at the end of last season.
The former Barcelona and Benfica midfielder is manager Phil Brown's second summer signing as he prepares for the club's first season in the Barclays Premier League.
Geovanni joined City on a free transfer from Cruzeiro last year but failed to make a huge impact at Eastlands.
Assistant manager Brian Horton told BBC Radio Humberside: "He's got a very good track record so I think he'll be an excellent signing for us.
"We've heard a lot about him and spoken to quite a few people, but we saw him ourselves so we know the player."