Minor and under-21: 2006–2010 Murphy experienced under-age success with
Donegal as a member of Donegal's 2006
Ulster Minor Football Championship-winning side. He captained the 2010
Ulster Under-21 Football Championship-winning side, contributing 0–1 in the three-point quarter-final victory over
Armagh, 1–2 (including two frees) in the four-point semi-final victory over
Derry and 1–5 (including two frees) in the comprehensive final victory over
Cavan, with all three games played at neutral
Brewster Park. He then played in the final of the
2010 All-Ireland Under-21 Football Championship, which Donegal (managed by
Jim McGuinness) narrowly lost to
Dublin (managed by
Jim Gavin). Murphy scored two frees and battled against future Dublin star
Rory O'Carroll.
Early years at senior level: 2007–2010 Murphy made his senior debut for Donegal in January 2007 against UUJ in the
Dr McKenna Cup. At the end of the 2009 season, he received the
All Stars Young Footballer of the Year, having scored 36 points in six
All-Ireland Senior Football Championship appearances, sixteen of them from play.
Jim McGuinness and Donegal captaincy: 2010–2014 In December 2010, the newly appointed Donegal manager
Jim McGuinness named Murphy captain ahead of the 2011 season. Succeeding
Kevin Cassidy in the role, Murphy became one of the youngest skippers in the county's history. The decision to select such a young man as team captain was unexpected. Donegal went on to reach the All-Ireland SFC semi-final, where they suffered a narrow defeat to eventual champions
Dublin in an extremely close match. In 2012, Murphy became the first player to captain Donegal to back-to-back Ulster titles, and later added the All-Ireland title—only the second Donegal captain to lift the
Sam Maguire Cup, after
Anthony Molloy in
1992. Although Murphy's scoring totals decreased after 2011, McGuinness praised him for his work rate and unselfish play. Murphy smashed the ball into the
Mayo net after three minutes of the
2012 All-Ireland Senior Football Championship Final, having collecting a high ball delivered by
Karl Lacey. That catch and strike was widely hailed as 2012's iconic score and Goal of the Season. Upon climbing the Hogan Stand after the game, lifting the Sam Maguire Cup and catching his breath, Murphy was handed a microphone to make his speech. He began by bellowing "We have him"—in reference to the Sam Maguire Cup. Murphy won his first All Star and attended the Football Tour of New York. Murphy opened the 2013 season on 2 February with nine points against Kildare in the opening league game at Croke Park. Analysts praised the skills he displayed throughout that game; at one point in the second half he stretched high into the air to meet a miscalculated free from Paddy McBrearty and gave it an almighty thump with his fist over the bar, while on another occasion he left the Kildare defender stumbling along the ground as he sidestepped him and casually at an angle from distance, with the appearance of little effort whatsoever, kicked the ball over the bar. Against
Tyrone on 3 March, he scored three from four of Donegal's points and then, shortly before half-time, having had a penalty saved by TG4 Man of the Match
Niall Morgan, Murphy struck out and was issued with a second yellow card by
Joe McQuillan. Against
Kerry on 10 March, man of the match Murphy dispatched a penalty and five points in Donegal's comfortable victory over the league's whipping boys.
Bonner–McGuinness interim and retention of captaincy: 2014–2017 One of the more memorable moments of 2015 from Murphy was his touch to
Ryan McHugh for Donegal's second goal in their Championship victory over
Galway at Croke Park. It was considered one of the goals of the season. He also scored 0–8 (five of which were frees) in the next game against Mayo, at the same venue. Murphy had earlier (in the
2015 National Football League) scored 1–3 (consisting of one penalty, two frees and one 45) against Kerry at
Austin Stack Park before scoring six points against Tyrone in the next game (five in the first half, four of these frees, three of which RTÉ described as "monster efforts" from a distance of sixty metres). Though he did not score from play, he gave a noteworthy performance against Armagh in the
2015 Ulster Senior Football Championship quarter-final and converted five frees. In the opening fixture of the
2016 National Football League away to Down, Murphy scored 0–8 (seven of which were frees). He scored 1–4 (0–2 of which were frees, 0–1 of which was from a '45) in the fourth fixture, away to Kerry at
Austin Stack Park. He scored another 0–7 (four of which were frees) against Roscommon in the next game. In 2017, Murphy was bothered by injuries to the groin and knee. He also scored an injury-time point from a free to secure a draw against Dublin in the same competition. Murphy later scored 0–7 (including four frees) against Monaghan, again in the league. It was in this game that Murphy became Donegal's
all-time record scorer, surpassing
Colm McFadden's record.
Declan Bonner, retention of captaincy and initial retirement: 2017–2022 He returned in early 2018 to play Dublin in the
2018 National Football League at Croke Park. Described by one commentator as "out-of-form and sluggish", he was commended for staying behind to do extra runs in an empty stadium. His form in 2018 was considered to be a return to his best. He scored 0–9 (including three frees and a '45) against Roscommon in the
2018 All-Ireland Senior Football Championship. In January 2019, it was announced that Murphy had undergone knee surgery and would miss the opening fixtures of the
2019 National Football League. He returned against Armagh nearly two months later, scoring a decisive one goal and two points in a substitute appearance that helped his county to a narrow one-point win. Against Kildare in the final round of the league, his presence was critical to the outcome of the match, which ended in Donegal's favour. Donegal qualified for the National Football League Division 2 final and Murphy started the game in an advanced role, scoring 0–7 (including five frees and two marks) in a man-of-the-match performance as Donegal defeated Meath to win the title. Murphy scored 1–7 (including 0–4 in frees) against Kerry in their 2019 All-Ireland Senior Football Championship quarter-final meeting at Croke Park. The goal was a penalty. As he set himself to take that penalty, a line of stewards in neon-coloured coats walked behind the goal. In the
2020 National Football League, Murphy endured two Dublin players "hanging out of him" in their one-point loss to the five-times reigning All-Ireland champions at Croke Park. Analysts on
League Sunday condemned the "cynicism" from Dublin, "the way they closed out the game", and called for it "to be stamped out".
RTÉ.ie stated: "On Saturday evening at Croke Park we were served up another undedifying
denouement". He scored six points from play against Armagh in the
2022 Ulster Senior Football Championship quarter-final and
The Irish News described him as "finish[ing] the game looking flying-fit". Ahead of the
2023 season, Murphy announced his retirement from inter-county football on 16 November 2022, ending his 15-year senior career. He released a statement via the county board. Murphy's retirement, at the age of 33, was unexpected.
Return under Jim McGuinness: 2024– In November 2024, it was announced that Michael Murphy would come out of retirement and again represent the county, under the manager that he captained them to the All Ireland This meant Murphy departed a role he had on the Football Review Committee. Live on television, in the
2025 National League meeting of Armagh and
Donegal at
MacCumhaill Park, Armagh's
2024 All-Ireland SFC-winning captain
Aidan Forker headbutted Michael Murphy in the 44th minute. This was within moments of Murphy's reintroduction (as a substitute) to inter-county football, and referee
Sean Hurson sent Forker off. Forker's headbutt of Michael Murphy was widely compared to
Zinedine Zidane's headbutt during the 2006 FIFA World Cup final, though — unlike Zidane's opponent — Murphy stood firm and did not even move. Murphy's extraordinary form in the
2025 All-Ireland SFC led Donegal to the final against Kerry. ==Inter-provincial==