The 31-year-old has joined the Serie A outfit after signing a two-year deal that includes an option to extend his stay by a further 12 months.
The midfielder started out with Real Betis before moving to Valencia in 2006, ending five years with Los Che when transferred to Malaga.
The last of his 51 caps for his country came in 2007, and Joaquin is pleased that his move to La Viola is complete after lengthy negotiations.
"I chose Fiorentina because there were several weeks of (Fiorentina technical director Eduardo) Macia telling us of the Viola's plans," he said.
"I was sure it was time to play in Italy, it will be a good experience."