The 39-year-old has been heavily linked with a move to Ligue 1 outfit Monaco, who dispensed of the services of Claudio Ranieri earlier on Tuesday, and this latest development will only serve to fuel those rumours.
Announcing Ranieri's exit, Monaco vice-president Vadim Vasilyev had stated there were "still some details to sort out" before they could identify their new coach.
Jardim only arrived in Lisbon from Olympiacos last year, but told reporters he was looking to take a step forward in his career, while Sporting president Bruno de Carvalho thanked him for his service.
"We have a sense of respect and friendship with Leonardo Jardim," said De Carvalho. "We spent a very good year together and we are not repenting of his decision.
"It's the end of an important cycle, however, we are saddened by his departure."
Jardim led Sporting to a second-placed finish in the Primeira Liga this season, ending the campaign seven points adrift of champions and city rivals Benfica.
