Shamrock Rovers are the 2020 SSE Airtricity League Premier Division champions, claiming their first title since 2011.
The Dublin side won the title without kicking a ball after their closest challengers Bohemians fell to a surprise 2-0 defeat at home to Finn Harps.
The result, courtesy of two Mark Russell goals, also sees 2017 double winners Cork City relegated to the First Division.
Stephen Bradley's Rovers play Derry City in Tallaght Stadium at 6pm on Wednesday.
It is The Hoops' 18th title in total, moving them four clear of Dundalk in the roll of honour. Their rivals from County Louth had won five leagues since Michael O'Neill's Shamrock Rovers won back-to-back titles in 2010 and 2011.
At Dalymount on Saturday evening, second-in-the-table Bohemians started with intent, Danny Grant galloping forward down he left to rifle a shot over the crossbar with just 35 seconds on the clock.
Unchanged from their last outing in holding outgoing champions Dundalk scoreless, Harps responded when forcing two early corners which Bohemians ably defended.
Gypsies’ Keith Ward then had the first real sight of goal on 19 minutes, latching onto skipper Keith Buckley’s through ball only to scuff his shot which Mark McGinley saved.
Looking a little unsure defensively, Harps had another let-off on 26 minutes when a James Finnerty header from Anto Breslin’s corner struck Shane McEleney.
A delightful move then deserved to give Bohemians the lead three minutes later.
Promise Omochere collected Buckley’s pass to thread a ball in for the run of Ward who shot just off target.
If shaky at the back, Harps were very much a threat when they got forward.
Substitute Adam Foley and Barry McNamee had shots bravely blocked before Tony McNamee brought a terrific diving save from James Talbot with a drive from distance.
McGinley did well back in the opposite goalmouth on 35 minutes, taking the ball off the head of Andrew Wright from Andy Lyons’ delivery into the near post with Harps scrambling the loose ball clear.
But it was Bohemians’ failure to clear their lines back at the other end that led to Harps taking the lead in first half stoppage time.
Tony McNamee’s long throw wasn’t dealt with. Kosovar Sadiki headed the ball back goalwards where Russell flicked it past Talbot from close range.
Harps stunned Bohemians further six minutes into the second half.
Foley’s cross from the right found Russell in acres of space inside the area.
And the winger’s drive may have taken a slight deflection to nestle in the far left-hand corner of Talbot’s net.
Minutes later Bohemians boss Keith Long made no fewer than four changes as the home side pressed frantically to get back into the game.
McGinley wasn’t found wanting under the pressure, excelling with a superb double save on 64 minutes from Grant and 16-year-old Evan Ferguson’s follow-up.
Minutes later the Harps keeper was there again to thwart Bohemians with a stunning stop to push Ferguson’s shot onto a post.
But Bohemians hopes of getting back into the game were dashed on 74 minutes when left-back Breslin received a straight red card after appearing to kick out at Leo Donnellan on the ground.
Harps midfielder Donnellan was then also sent off for a rash challenge on Finnerty with five minutes to go.
Bohemians: James Talbot; Andy Lyons, James Finnerty, Michael Barker, Anto Breslin; Keith Buckley (JJ Lunney 88), Conor Levingston (Dawson Devoy 56); Promise Omochere (Jack Moylan 56), Keith Ward (Ross Tierney 56), Danny Grant; Andre Wright (Evan Ferguson 56).
Finn Harps: Mark McGinley; Shane McEleney, Kosovar Sadiki, Stephen Folan; Gareth Harkin, Leo Donnellan; Dave Webster, Tony McNamee (Ryan Connolly 72), Mark Russell; Karl O’Sullivan, Barry McNamee (Adam Foley 16; Raff Cretaro 90+4).
Referee: Neil Doyle (Dublin).