Striker Paulinho struck the only goal of the game in the 36th minute, taking unbeaten Sporting, who are still unbeaten with two games left, to 82 points after 32 matches, an unassailable eight-point advantage over second-placed Porto.
Thousands of excited fans bearing the club's white and green colours gathered outside Sporting's Jose Alvalade stadium before kickoff, waving flags and shouting "Champions!" although no fans were able to enter the ground due to coronavirus restrictions.
Police had warned fans not to gather in large groups and urged them to practice social distancing and wear a mask at all times, with spokesman Domingos Antunes saying he hoped the celebration would not turn into a "nightmare."
Ruben Amorim's side saw out the win to claim the club's 19th league title and end rivals Porto and Benfica's 19-year stranglehold on the championship.
For some younger fans amongst the huge gathering it was the first time they had experienced their club winning the title.
Portugal captain Cristiano Ronaldo, who plays for Juventus, took to social media to congratulate Sporting, where he began his career. "Many congratulations champions," he wrote on Instagram.
Sporting's relentless campaign was hard to envisage when they finished fourth last season, 22 points behind champions Porto, and were struggling to fill the hole left after talismanic captain Bruno Fernandes joined Manchester United.
The title win completed a huge turnaround in fortunes for the club three years after the squad was attacked by angry fans at the training ground.