|Date of birth||6 March 1971|
|Place of birth||Collepardo, Italy|
|* Senior club appearances and goals counted for the domestic league only.
† Appearances (Goals).
Atzori started his professional playing career with Rome-based Serie C side Lodigiani in 1988, then playing mostly at Serie B level with several teams, including Perugia, Reggina and most notably Ravenna, where he spent a total four season. In 2001 he joined Empoli, being protagonist of the Tuscans' successful 2001–02 Serie B campaign which saw the team being crowned league winners under head coach Silvio Baldini. He then played another season with Empoli, in his personal first (and only) Serie A season. In 2003 he followed Silvio Baldini at Palermo, who later won the Serie B title in 2003–04; he played only 17 league games out of 46 with the rosanero, being relegated to the bench after Silvio Baldini's dismissal from the head coaching post.
After being released by Palermo in June 2004, Atzori chose to retire from football and instead focus in a management career, becoming Silvio Baldini's assistant at Parma. He then followed again Baldini also in his unsuccessful stints at Lecce (2005–06) and Catania (2007–08), both ended in his boss and mentor being sacked in mid-season. However, after Baldini was sacked from Catania in April 2008, Atzori decided instead to stay under new boss Walter Zenga.
In June 2008 Atzori left Catania to accept a head coaching offer from Lega Pro Prima Divisione side Ravenna, a team where he had already spent four seasons as a player. He guided Ravenna through a very impressive season and qualification into promotion playoffs, where Ravenna was defeated by Padova in the semi-finals.
On 10 June 2009 Atzori accepted to return at Catania, this time as head coach, for the upcoming 2009–10 season, thus replacing his former head coach Walter Zenga at the helm of the rossoazzurri. However, his time back at Catania lasted only fifteen games, as he was dismissed on 8 December due to poor results.
On 9 June 2011 Atzori was named as the new head coach of Sampdoria have been relegated to Serie B, signing a two-year contract. After a disappointing start of season, with Sampdoria in seventh place despite being tipped as one of the main direct promotion candidates during pre-season, Atzori was ultimately sacked on 13 November 2011.
On 4 January 2013 he was named new coach of Spezia in Serie B en place of the sacked Michele Serena. His stint was however short-lived as he was sacked weeks later due to poor results and replaced by Luigi Cagni.
On June 2013 he was named as the new head coach of Serie B club Reggina, thus marking a personal second stint of his at the Calabrian club. He was sacked in October 2013 and replaced by Fabrizio Castori, but reinstated in December 2013.
- "Il Catania annuncia Atzori" (in Italian). Sportal.it. 10 June 2009. Retrieved 10 June 2009.
- "Gianluca Atzori è il nuovo allenatore del Catania" (in Italian). Calcio Catania. 10 June 2009. Retrieved 10 June 2009.
- "Sinisa Mihajlovic è il nuovo allenatore del Catania" (in Italian). Calcio Catania. 8 December 2009. Retrieved 8 December 2009.
- "Atzori alla Reggina. Lunedi' la presentazione" (in Italian). Reggina Calcio. 16 June 2010. Retrieved 17 June 2010.
- "Gianluca Atzori è il nuovo tecnico" (in Italian). U.C. Sampdoria. 9 June 2011. Retrieved 9 June 2011.
- "U.C. SAMPDORIA: COMUNICATO STAMPA 13 NOVEMBRE 2011" (in Italian). U.C. Sampdoria. 13 November 2011. Retrieved 13 November 2011.
- "LA REGGINA RIPARTE DA GIANLUCA ATZORI" [REGGINA STARTS AGAIN WITH GIANLUCA ATZORI] (in Italian). Reggina Calcio. 17 June 2013. Retrieved 6 July 2013.
- "Reggina: in panchina torna Atzori" [Reggina: Atzori back on the bench] (in Italian). Gazzetta dello Sport. 3 December 2013. Retrieved 14 December 2013.