In July 2004, Dainelli signed for newly promoted team Fiorentina, in a co-ownership deal with Brescia.

Dainelli was the team captain after Christian Riganò left the club in summer 2005,[citation needed] a position which he hold until his transfer to Genoa.

In summer 2009, ACF Fiorentina prepared to sell the captain by signing Cesare Natali in order to increase the depth of the bench.

[3] On 31 January 2012, the last day of 2011–12 winter transfer window, Dainelli moved to the fellow league club Chievo Verona on a loan deal.

[7] Dainelli made his debut for the Italy national team against Ecuador on 11 June 2005 a friendly match which ended in a 1–1 draw.