Born in Birkenhead, Wirral, Power joined local Tranmere Rovers' youth set-up at the age of eight and captained the club at every age group including the first team.[2] He chose to join the team instead of signing for Liverpool.[4] After impressing in the Tranmere Rovers Reserve team he was awarded a professional contract in May 2011.[5] Manager Les Parry was confident Power had a bright future in the game, but warned the youngster about his aggression.[6] He compared him to Joss Labadie, another young and talented Rovers midfielder with a reputation as a hothead.[7] Power spent time on loan at Colwyn Bay in the 2010–11 season.[8]
2011–12 season
Power made his first team debut in the Football League Trophy clash with Port Vale on 30 August 2011; he replaced Andy Robinson on 66 minutes before he went on to score a penalty in the penalty shootout victory.[9] On 10 September he made his League One debut, starting in a 0–2 defeat away to Huddersfield Town and making way for Labadie after 77 minutes.[10] He ended his first season with four league appearances and two in the Football League Trophy.
2012–13 season
Power scored his first goal for the club on 13 November 2012, concluding a 3–0 win against Braintree Town in the FA Cup first round after coming on for James Wallace.[11] He scored his first league goal for the club on 26 December, as they came from behind to win 2–1 against Crewe Alexandra at Prenton Park.[12] On 4 March, he extended his contract, keeping him at the club until June 2015.[13]
2013–14 season
In the following season, Power scored his first goal on 15 March 2014, equalising in the 15th minute of an eventual 1–2 home defeat by Swindon Town.[14] His only other goal of the campaign was on 12 April, opening a 2–1 home win over Shrewsbury Town;[15] both teams were relegated at the end of the season.
2014–15 season
On 7 October 2014, Power opened the scoring as Tranmere drew 1–1 at home against Carlisle United in the Football League Trophy second round, advancing via a penalty shootout.[16] He scored the only goal in the FA Cup first round against Bristol Rovers on 8 November, converting a penalty after handball by Mark McChrystal.[17] Three days later, he equalised as Tranmere came from behind to win 2–1 at Bury in the quarter-finals of the Football League Trophy.[18]
He opened the scoring in the semi-finals on 9 December, a 2–2 draw against Walsall, and scored in the shootout although his team were knocked out.[19] A week later, Power concluded a 2–1 comeback to defeat Oxford United in an FA Cup second round replay.[20] He again netted in the third round on 3 January 2015, albeit in a 2–6 defeat to Premier League club Swansea City.[21] On his 100th league appearance for Tranmere, he opened the scoring in a 2–1 win away to Cambridge United on 17 March.[22] Tranmere needed to win away at Plymouth Argyle on 25 April to retain their place in The Football League, but Power fouled Dominic Blizzard to concede a penalty which Reuben Reid scored. He equalised from the edge of the penalty area, but his team lost 2–3, and thus were relegated to the Conference, ending a 94-year tenure in the league.[23]
Wigan Athletic
On 3 July 2015, Power signed for Wigan Athletic on a three-year contract.[24] He scored a free-kick in the club's first pre-season match, a 2–1 win against Queen of the South in La Manga Club.[25] On 9 August he played the full 90 minutes as Wigan began the League One season with a 2–0 defeat to Coventry City at the Ricoh Arena.[26] On 26 September, he scored his first goal for Wigan in a 1–1 draw at Oldham Athletic, opening the scoring from 30 yards.[27]
Sunderland
On 9 August 2018, Power signed for Sunderland on loan from Wigan Athletic.[28] During his loan spell, Power received three straight red cards against Oxford United, Bradford City and Walsall, although the latter was rescinded 2 days later.[29] On 2 January 2019, Power's loan to Sunderland became permanent, signing a 2+1⁄2-year contract.[30] Power also went on to make appearances in both the 2019 EFL Trophy Final and the League One play-off final, suffering defeat in both.[31][32] Power was named Sunderland's team captain at the beginning of the 2020–21 season.[33] He subsequently lifted the trophy following Sunderland's 1–0 win over Tranmere in the 2021 EFL Trophy Final.[34] On 25 May 2021 it was announced that he would leave Sunderland at the end of the season, following the expiry of his contract.[35]
Return to Wigan Athletic
On 16 June 2021, Power agreed to reunite with manager Leam Richardson ahead of the 2021–22 campaign on a two-year deal. In April 2022 Power picked up his third League One title with Wigan Athletic following a 3–0 victory over Shrewsbury Town.[36]