| Competition: | Donegal S.F.C. |
| Season: | 2021 |
| Winners: | St Eunan's (15th title) |
| Continentalcup5: | Ulster SCFC |
| Continentalcup1: | All-Ireland SCFC |
| Continentalcup2: | Winning captain |
| Continentalcup2 Qualifiers: | Niall O'Donnell |
| Continentalcup3: | Man of the Match |
| Continentalcup3 Qualifiers: | Shane O'Donnell |
| Continentalcup4: | Winning manager |
| Continentalcup4 Qualifiers: | Rory Kavanagh |
| Matches: | 46 |
| Prevseason: | 2020 |
| Nextseason: | 2022 |
The 2021 Donegal Senior Football Championship was the 99th official edition of Donegal GAA's premier Gaelic football tournament for senior graded clubs in County Donegal. 16 teams competed, with the winner representing Donegal in the Ulster Senior Club Football Championship.
Naomh Conaill was defending champion after defeating Cill Chartha in a penalty competition held after extra-time of the 2020 final.
Naomh Conaill advanced to the 2021 final, but lost to St Eunan's.
The following teams changed division since the 2020 championship season.
Promoted from 2020 Donegal I.F.C.
Relegated to 2021 Donegal I.F.C.
The competition began with a league stage.[1] The draw for the first two rounds was held in June 2021, with the identity of the 2020 Championship winner still unknown, a first such event in the competition's history.[2]
Gaoth Dobhair and Naomh Conaill, the last two clubs to win the competition, were paired with each other in the quarter-final draw. Seán MacCumhaills and Kilcar met in the other quarter-final on that side of the draw. On the other side of the draw St Eunan's and St Naul's played each other in one quarter-final, while St Michael's and Aodh Ruadh played each other in the other quarter-final.[5]
The semi-final meeting of Kilcar and Naomh Conaill was shown live to a national audience on TG4.[6] Naomh Conaill won, after a late Patrick McBrearty goal that would have brought the sides level, was ruled out.[7]
It was Naomh Conaill's fifth consecutive appearance in the final.[5] The game was televised live on TG4.[7] A minute's silence was held before the game in memory of Martin Griffin, whose sudden death occurred the previous day.[8] St Eunan's won.[9]
Eight clubs (Glenfin, Glenswilly, Réalt na Mara, Ard an Rátha, Milford, Na Cealla Beaga, Termon and Four Masters) entered the draw for the relegation play-offs once the quarter-final line-up was confirmed.[10]
See main article: 2021 Ulster Senior Club Football Championship and 2021–22 All-Ireland Senior Club Football Championship.
St Eunan's advanced to the 2021 Ulster Senior Club Football Championship.
Watty Graham's knocked St Eunan's out of that competition with an injury time point from Danny Tallon winning the game at O'Donnell Park, despite St Eunan's scoring the only goal and leading for much of the game and Shaun Patton saving a penalty.[11]
Caolan Ward was named as the recipient of the annual Gradam Shéamuis Mhic Géidigh.[12]
The following matches were broadcast live on national television, unless otherwise indicated:
| Round | RTÉ | TG4 |
|---|---|---|
| Semi-finals | Naomh Conaill v Kilcar | |
| Final | St Eunan's v Naomh Conaill | |
| Rank | Player | Club | Tally | Total |
|---|---|---|---|---|
| 1 | Kane Barrett | Milford | 2–25 | 31 |
| 2 | Michael Murphy | Glenswilly | 0–28 | 28 |
| Cian McEniff | Réalt na Mara | 2–22 | ||
| 4 | Oisín Gallen | Seán MacCumhaills | 1–23 | 26 |
| 5 | Gerard Ward | Glenfin | 0–23 | 23 |
| Philip Patton | Aodh Ruadh | |||
| 7 | Niall O'Donnell | St Eunan's | 1–19 | 22 |
| Charles McGuinness | Naomh Conaill | |||
| Patrick McBrearty | Kilcar | |||
| Stephen McBrearty | 0–22 | |||
| 11 | Michael Langan | St Michael's | 2–15 | 21 |
| Daire McDaid | Termon | 1–18 | ||
| 13 | Eoin McGeehin | St Eunan's | 3–10 | 19 |
| 14 | Peadar Mogan | St Naul's | 0–18 | 18 |
| 15 | Stefan Boyle | Ard an Rátha | 2–11 | 17 |
| C. J. Molloy | ||||
| Colm A. McFadden | St Michael's | 1–14 | ||
| Ryan McFadden | Termon | 0–17 | ||