Gary Twigg, who put the visitors in front in the first half, proved his worth to the Hoops with the decisive strike in the 57th minute when he swept the ball to the netfollowing a lapse in the Sligo defence.
The champions battled bravely to the end but they were never able to breach a rock solid Shamrock Rovers defence.
However, the result was all but forgotten once the championship trophy was handed over to Sligo skipper Danny Ventre after the final whistle.
Members of Sligo’s last league-winning side of 1977 and their manager BillySinclair were guests at the celebrations.
The game was stopped for a number of minutes early in the first half when a section of Shamrock Rovers supporters hurled flares on to the pitch, order being restored when gardaí moved in.
Ross Gaynor threatened the visitors’ goal after two minutes of the first half but the vigilant Hoops defence cleared the danger.
Gary Twigg put the Hoops ahead in the 10th minute when his clever finish, after his first attempt had come back off the bar, caught the Reds off guard.
Gary McCabe had a great chance to double the visitors’ advantage after 25 minutes following a Billy Dennehy cross but the home goal survived, A shot by Joseph Ndo almost sneaked in at the other end on the half-hour mark.
Shamrock Rovers controlled the play in the opening half and remained cool and solid at the back whenever Sligo threatened their goal.
Sligo’s hard work had already been done.
SLIGO ROVERS: Rogers, Henderson (Owens 56), McGuinness, Peers, Gaynor, Millien (Dillon 67), Lynch, Ndo, Cawley, Cretaro, Quigley (Buchanan 80).
SHAMROCK ROVERS: Jansson, Sullivan, Powell, Oman, Gartland, McCormack, Brennan, McCabe, Dennehy,
Greene, Twigg (Ebbe 85).
Referee: Anthony Buttimer, Cork.