He then played during Gaoth Dobhair's first ever Ulster Senior Club Football Championship-winning campaign later in 2018, a run which involved a quarter final defeat of Cargin (a game in which Carroll scored a goal and three points),[4] a semi-final defeat of eleven-time winners Crossmaglen Rangers,[5] and culminated in the club defeating Scotstown (who had won the competition on four previous occasions), the last two of these games occurring at Healy Park in Omagh. Carroll thought he had won the Ulster final with a point in normal time but the referee ruled it out as a "throw ball" foul by Carroll's teammate who passed him the ball; extra time was required to separate the sides.[6][7][8]
First featuring for his county at senior level under the management of Rory Gallagher, Carroll made a number of appearances during Donegal's Division One campaign in the 2016 National Football League: first he started the league opener against Down,[12] then he made a substitute appearance against Cork in the second round of fixtures,[13] started against Mayo in the third round of fixtures[14] and, finally, made a substitute appearance against Dublin in the sixth round of fixtures.[15]
In the 2017 National Football League Carroll scored a goal against Monaghan to help Donegal to a draw.[16] He made his senior championship debut in the quarter-final of the 2017 Ulster Senior Football Championship.[17] He played a part in Donegal's opening goal (scored by fellow senior championship debutant Jamie Brennan) as his county defeated Antrim to progress to the semi-final.[18] In that semi-final, a loss to Tyrone, Carroll scored his first senior championship goal.[19]
^Craig, Frank (3 December 2018). "Carroll - 'These are special days'". Donegal News. Retrieved 3 December 2018. …Even at the end of normal time I'd that chance. It definitely wasn't a throw ball! I can't be too sore on Odhran (MacFadden-Ferry) I think the ref has to take the blame for that one! Seriously though, we had to dig so deep in extra-time…
^Ferry, Ryan (28 November 2019). "Bonner boosted by young guns return". Donegal News. p. 80. Gaoth Dobhair's Michael Carroll has earned a recall after some excellent displays in the middle of the field for his club in the Donegal SFC.
^Ferry, Ryan (19 October 2023). "Motivation not a problem for Regan and Naomh Conaill". Donegal News. p. 69. Dan McBride has retired, while Christopher Sweeney, Ódhrán McFadden-Ferry, Naoise Ó Baoill, Cian Mulligan, and Eamonn Collum are living outside the country, while Michael Carroll has been injured for much of the season.