Both Sporting and Benfica were level on points going into their last match after a tense 1-1 derby draw last weekend left the title race on a knife-edge.
Benfica needed to better Sporting's result to triumph but drew 1-1 at Braga, although even a victory would not have been enough as Rui Borges' side triumphed and had the superior head-to-head.
Pedro Goncalves broke the deadlock in the second half and the division's top goalscorer Viktor Gyokeres notched his 39th league goal of a stunning campaign to seal Sporting's victory.
Manchester United coach Ruben Amorim led Sporting to last year's title, and after he departed in Novembe,r was replaced by Joao Pereira, who only lasted six troubled weeks before Borges took over.
Sporting claimed their 21st Primeira division title and could make it a domestic double as they face Benfica next Sunday in the Portuguese cup final.
