With the arrival of new manager Pep Guardiola at Manchester City in 2016, Hart became the second-choice goalkeeper and made only one appearance in the Champions League before moving on loan to Torino and West Ham United in successive seasons.

[7] On 30 November 2005, the Shropshire Star newspaper reported that Everton goalkeeping coach Chris Woods had been present at Town's previous league match, a 4–3 loss at Rochdale.

[13] Hart made his debut for City on 14 October 2006 after injuries ruled out Andreas Isaksson and Nicky Weaver for the Premier League match against Sheffield United.

[27] He was then named in his then club manager Stuart Pearce's first squad in his part-time role as England U21 coach, alongside another goalkeeper uncapped at U21 level, Ben Alnwick.

[44] His performances improved:[45] against Chelsea in December, he "showed not only sharp judgment and reflexes, making three outstanding saves ... but a lack of fear also", despite needing staples in a gashed head sustained when diving at the feet of Salomon Kalou.

[72] On 24 February 2015, Hart saved a penalty kick from six-time FIFA Ballon d'Or winner Lionel Messi in a Champions League round of 16 fixture against FC Barcelona.

[73] After the return leg of the same tie Messi described Hart as a "phenomenon" after a performance where he made 10 saves during the match, a record for an English goalkeeper in the Champions League.

[75][76] Hart ended the 2014–15 season by keeping a clean sheet against Southampton in his 300th appearance for Manchester City to win the Premier League Golden Glove award for the fourth time.

[79] On 6 April 2016, Hart saved a penalty kick from Zlatan Ibrahimović in Manchester City's Champions League quarter-final first leg against Paris Saint-Germain at the Parc des Princes.

[83] Hart made his first start of the 2016–17 season in a Champions League qualifying match against Steaua Bucharest, as captain of the City side that won 1–0 on the night, 6–0 on aggregate.

[88] On 11 September 2016, Hart suffered a tough start in his debut for Torino, being partly at fault for the equaliser in a 2–1 away defeat to Atalanta when his punch from a corner fell at the feet of an opposing attacker who scored.

[92] Hart played in all 36 of Torino's remaining league matches in the 2016–17 season,[93] but in April the club's president Urbano Cairo suggested his level of performance had dropped amid transfer speculation.

[111] On 3 August 2021, after being told he was not part of new Spurs manager Nuno Espírito Santo's plans,[112] Hart signed for Scottish club Celtic on a three-year contract.

[113][114] Hart made his debut two days after signing in a 4–2 away win against Czech side FK Jablonec in the Europa League, but appeared uncomfortable during the match, particularly during Celtic's concession of a second goal.

[117] Hart made an error in the Europa League qualifying play-off match against AZ Alkmaar on 26 August 2021, failing to clear his lines and conceding as a result.

[119] Hart received plaudits for his performance against Hibernian on 27 October, denying a close-range Joe Newell effort and smothering a Jamie Murphy strike, helping Celtic to a 3–1 win.

[121] On 19 December 2021, Hart played the full 90 minutes as Celtic won the 2021–22 Scottish League Cup after defeating Hibernian 2–1 via a brace from Kyogo Furuhashi in the final.

[22] After making his under-21 debut as a substitute for Scott Carson in a 2–2 draw with Spain,[131] Hart was selected by Stuart Pearce in the 30-man preliminary squad for the 2007 UEFA European Under-21 Championship, and made the final 23.

[133] In the semi-final against Sweden, he conceded three goals in the second half as the match ended 3–3 after extra time, but made up for it by saving a penalty and scoring another as England won 5–4 in the shoot-out.

[34] However, Hart's senior England debut did not earn Shrewsbury Town the expected bonus of £500,000 from Manchester City, as negotiated as part of his transfer in 2006, because it was not a competitive match.

[137] After Blackburn Rovers goalkeeper Paul Robinson withdrew from the squad for World Cup qualifiers against Ukraine and Belarus in October 2009, Hart took his place,[138] and in November, he was called up for a friendly against Brazil,[139] but he did not appear in either match.

[145] Hart was given his first competitive cap in a UEFA Euro 2012 qualifier, a 4–0 win against Bulgaria at Wembley Stadium; he made three crucial saves, one of which he palmed away to begin the counterattack that led to an England goal.

[148] Hart won another two caps November 2011 in friendlies against world champions Spain and Sweden, in each case keeping a clean sheet in a 1–0 England victory.

[157] Hart made another mistake in a 2014 World Cup qualifying game against Poland on 17 October 2012, failing to punch clear a corner which led to a crucial equaliser that deprived England of a win.

[160][161] Earlier in the match a communication breakdown between Hart and defender Gary Cahill had presented Sweden with a clear opportunity to make it 2–0, and manager Hodgson said that it was "not one of Joe's best nights".

In October 2014, England fans voted Hart man of the match against San Marino – in which he made only one save and rarely touched the ball – and repeated the exercise a few days later against Estonia; Jack Wilshere was the official best player in each fixture.

[175] In October 2016, Hart put up one of the best performances of his career, producing a "stunning saves-show" in their 2018 FIFA World Cup qualifier against Slovenia to secure a 0–0 draw.

[176] However, in a match during a World Cup qualifier against arch-rivals Scotland on 10 June 2017, Hart conceded two goals directly from free kicks for the second time in his England career.

[177][178] These calls increased after Hart put in a further unconvincing performance against Slovakia on 4 September 2017, in which he made an error in allowing an early Stanislav Lobotka goal and an important second-half save from Adam Nemec.

[186] However, Hart also came under criticism from pundits and managers throughout his career for his perceived poor distribution, positioning, and ability to defend crosses, as well as for his inconsistency and tendency to commit technical errors, in particular following some high–profile mistakes on long range shots at Euro 2016, after which he suffered a noticeable decline in the level of his performances.