Conti started his career at AS Roma, in mid-1999, he was sold to Cagliari in a co-ownership deal. He did not leave the club despite the club being relegated in 2000. In June 2004, he was in the team when they were the runner-up of Serie B and returned to Serie A after 4 seasons. After the retirement of long-serving Uruguayan defender Diego López in 2010, Conti has become the new team captain.