Mathieu had been training with the Portuguese side with a view to earning a contract with the club, and Barca confirmed on Friday that they had agreed to terminate his contract at Camp Nou.
The Frenchman still had 12 months remaining on his deal with the Catalans but is not part of new manager Ernesto Valverde's plans for the 2017-18 campaign.
And, having done enough to convince Sporting, the Primeira Liga side have now confirmed that they have signed the 33-year-old.
A statement on the club's official website read: "Sporting Clube de Portugal - Futebol, SAD announces that it has reached an agreement with the player Jeremy Mathieu to sign a contract valid for the next two seasons and with a termination clause set at €60 million.
"Sporting SAD wishes Jeremy Mathieu the greatest professional and personal happiness."
Barcelona, meanwhile, issued a statement confirming Mathieu's exit and wished the player luck for the future.
"FC Barcelona and Jermy Mathieu have agreed to terminate the player's contract, after three full seasons at the club.
"Mathieu, 33, joined FC Barcelona in the summer of 2014, with Luis Enrique taking over at the same time. In his time with the club, the Frenchman won nine titles: three Copa del Rey, two La Liga titles, a Champions League, a Club World Cup, a European Super Cup and a Spanish Super Cup.
"In total, Mathieu played 91 times and scored four goals, three in the league and one in the cup.
"FC Barcelona wishes the player the best of luck and success in his next professional step."