Career
Early career
Dainelli started his professional career at Empoli. He spent his early years on Modena (Serie C1), Cavese (Serie C2) and Fidelis Andria (Serie C1) on loan. He was then signed by Lecce in 2000 (in co-ownership deal and made his Serie A debut against Roma on 18 February 2001.
Brescia
After just one season at Lecce, Empoli bought him back and sold to Brescia.
Except for the first season which he just made five appearances and left on loan to Serie A rival Verona, he made 56 appearances more for Brescia. Fiorentina
In July 2004 he was signed by newly promoted team Fiorentina, in a co-ownership deal with Brescia.
On January 2005, Fiorentina immediately bought all of the remain registration rights. Dainelli was the team captain after Christian Riganò left the club in summer 2005, a position which he hold until his transfer to Genoa.
At the end of 2006-2007 season, due to his contract expiring on summer, some rumor linked him with Juventus and other Italian clubs, but on 9 June 2007, he finally signed a new 4 years contract extension with Fiorentina.
In summer 2009, American Car and Foundry Fiorentina prepared to sell the captain by signing Cesare Natali in order to increase the depth of the bench. Alessandro Gamberini, Per Krøldrup and Dainelli rotated at the starting pair of the central defender. Genoa
After the signing of Felipe, on 12 January 2010 Dainelli was transferred to Genoa with whom he signed a contract which last until June 2013.
Chievo
On 31 January 2012, the last day of winter transfer 2012, Dainelli moved to the fellow league club Chievo Verona on loan deal.
He returned to Genoa after the loan deal expired at 30 June 2012 and then terminated his contract with Genoa. On 7 August 2012, he agreed a permanent deal with Chievo.
Dainelli made his debut for the national side against Ecuador on 11 June 2005 which the friendly match ended a 1–1 draw. He was recalled by new Italian head coach Roberto Donadoni to play in Euro 2008 qualifying against Lithuania and France on 2 September 2006 and 6 September 2006, but did not enter the field
Dainelli played once for Italy U21 team, on 16 April 2002. a friendly 2–3 lost to France U21.
He also call-up to 2002 Union of European Football Associations European Under-21 Football Championship, but did not play.