[4][5][6][7][8][9] Di Canio began his career in the Italian Serie A, playing for Lazio, Juventus, Napoli and Milan, before a brief spell with the Scottish club Celtic.

He subsequently spent seven years in the English Premier League with Sheffield Wednesday, West Ham United and Charlton Athletic.

He played for the Italian under-21s, making nine appearances and scoring twice, and was a member of the squad that finished in third place at the 1990 UEFA European Under-21 Championship under manager Cesare Maldini, but was never capped for the senior team.

However, his career was at times characterised by controversy: he received an eleven-match ban in 1998 for pushing a referee and attracted negative publicity over his allegiance to fascism.

In 1990, he was sold to another of Italy's biggest clubs, Juventus;[12] although he won the UEFA Cup with the Turin side in 1993, he struggled to gain playing time during his tenure with the club, because of the presence of other forwards and creative midfielders in the team, such as Roberto Baggio, Salvatore Schillaci, Pierluigi Casiraghi, Fabrizio Ravanelli, Gianluca Vialli and Andreas Möller.

[12] On 6 August 1997, Di Canio moved to the English Premiership as he joined Sheffield Wednesday in a transfer deal valued at around £4.2 million.

In September 1998, Di Canio pushed referee Paul Alcock to the ground after being sent off while playing for Sheffield Wednesday against Arsenal at Hillsborough, which resulted in an extended ban of eleven matches.

West Ham manager Harry Redknapp, on signing Di Canio, admitted he was taking a chance but said of the player "He can do things with the ball that people can only dream of".

In December 2000, late in a game against Everton and with both sides vying for the winning goal, Di Canio shunned a goal-scoring opportunity and stopped play, grabbing the ball from a cross inside the box, as the Everton goalkeeper Paul Gerrard was lying injured on the ground after he twisted his knee attempting a clearance on the edge of the box.

[26] In 2003, with the Hammers struggling at the bottom of the league, Di Canio had a very public row with manager Glenn Roeder and was dropped from the first team.

[30][31] Di Canio also continued to be a provider of goals, however, notably in October 2003 when he came on as a second-half substitute with Charlton trailing 1–0 away at Portsmouth.

During several of his games for Lazio – including during goal celebrations – Di Canio made a fascist salute to their right-wing fans.

[36] In an interview he revealed that his dream would be to manage former club West Ham, and applied for the position after the resignation of Alan Curbishley in September 2008.

A talented yet controversial player, Di Canio was predominantly known for his creativity, eye for goal, technical ability, and dribbling skills, as well as his quick feet and intelligent play on the pitch, and was described as having "an eye for the spectacular" by The Irish Times in 2001, and as a "mercurial" player by Chris Howie of beIN Sports in 2020; however, he was equally known for being inconsistent and for his temperamental character, as well as his tenacity and aggression on the pitch.

[47] On 30 August 2011, Di Canio was involved in a pitch-side altercation with Swindon striker Leon Clarke after their defeat in the League Cup to Southampton.

Di Canio stated that he believed his players deserved to have their names put on the stadium and dedicated the victory to his father, who died late in 2011.

[51] On 21 April 2012, Swindon were promoted to the League One after Crawley Town's 1–1 draw with Dagenham & Redbridge and Torquay United's 2–0 loss to AFC Wimbledon, despite Di Canio's side having lost 3–1 to Gillingham on the same day.

Di Canio offered to pay £30,000 of his own money to keep loan players John Bostock, Chris Martin and Danny Hollands at the club.

[58] With the possibility of the club entering administration, a new buyer was found, subject to Football League approval, and without the knowledge of Di Canio, player Matt Ritchie was sold to AFC Bournemouth.

[59] On 31 March 2013, Sunderland appointed Di Canio as manager on a two-and-a-half-year contract, following the dismissal of Martin O'Neill the previous day.

[60] The appointment prompted the immediate resignation of club vice-chairman David Miliband over Di Canio's "past political statements".

[74] Sunderland chief executive officer Margaret Byrne stated that Di Canio had been sacked after senior players had approached her and that his situation became untenable because of his "brutal and vitriolic" criticism of the squad.

[76] Di Canio was linked with the Celtic job in May 2014,[77] and applied for vacant managerial positions at Bolton Wanderers in October 2014,[78] and Rotherham United in September 2015[79] and again in February 2016.

[61] It also met opposition from the Durham Miners' Association,[62] which threatened to remove one of its mining banners from Sunderland's Stadium of Light, which is built on the former site of the Wearmouth Colliery, as a symbol of its anger over the appointment.

[91][92] In a profile piece in 2011, an unnamed source asserted that Di Canio was not "an ideological fascist", attributing his behaviour to "his psychological history, particularly his former compulsive tendencies and pronounced mood swings".

"[86] Di Canio has several tattoos, including on his right biceps the Latin word "DUX", meaning "leader" or, in Italian, Il Duce—a nickname for Benito Mussolini.

[93] Sky Sports Italia was forced to apologise after Di Canio appeared as a pundit in September 2016 in a short-sleeved shirt, thus revealing the tattoo to television viewers; he was later suspended by the station.

[97] Di Canio has spoken also of the growing influence in his life of Samurai culture, and of the Japanese spiritual mentality from reading Mishima, and the teachings in the traditions of Hagakure and Bushido.