Abate started playing football with amateur club Rescaldina, before joining Milan’s youth system in 1999. During the 2003–04 season, he made his professional debut, playing in a Coppa Italia game against Sampdoria on 3 December. Ignazio Abate also made his debut in European competitions, in a Champions League group-stage game versus Celta Vigo on 9 December. In that match he set the record as the youngest Milan player to ever play in the UEFA Champions League, at 17 years and 27 days.
Various loan spells (2004–2007)
For the 2004–05 season he was loaned out to Napoli in Serie C1, where he made 29 appearances and scored 2 goals. In the summer of 2005 he had been set to spend the following season on loan at Serie A side Sampdoria. However, prior to the actual start of the competitions, he was called back and loaned to Piacenza instead, though he only made 13 appearances in his first Serie B season. The following one was more successful for the young winger, who made 38 appearances during his loan spell at Modena.
Serie A debut (2007–2009)
In the 2007–08 season Ignazio Abate eventually made his Serie A debut, after being acquired by Empoli in a co-ownership deal, for €900,000. That year, he also scored his first goal in Serie A, in a match against Genoa, on 27 April 2008. Following Empoli’s relegation, Milan fully purchased him for €2 million as well as Luca Antonini for €2.75M (and sold Nicola Pozzi and Lino Marzoratti for €4.75M total fee) only to send him to Torino in another co-ownership deal, for €2 million. Despite an early injury, he had a good season, appearing in 25 games and scoring 1 goal.
Back to Milan
On 24 June 2009, Milan reclaimed Ignazio Abate for €2.55 million and this time he was included in the team roster for the upcoming 2009–10 season. After serving mainly as a reserve midfielder in the first few games, he later started to be employed as the regular right back by Milan head coach, Leonardo. He made 36 appearances in his first season back at Milan. Due to his good performances, on 11 February 2010 he was offered and signed an extension to his contract until 2014.
New coach Allegri kept him in the same position for the 2010–11 season. His dribbling skills and speed in the right wing allowed him to outrun opponent defenders, while his crossing into the centre also resulted in goals regularly. His solid defensive play also lent a hand in winning Milan their 18th Scudetto and the Supercoppa Italiana. He made 37 appearances in total in his second season back at Milan. The following season, Abate was again the starting right back at Milan, making 40 appearances in all competitions. In the 2013–14 season, Abate scored his first Milan goal in a 3–3 draw with Bologna on the 25 September 2013
In the 2014–15 season, Abate captained Milan for the first time in his career, the first time in a 2–0 loss to Palermo on the 2 November 2014. Ignazio Abate made his 200th Milan appearance on the 9 May 2015, in a 2–1 win over Roma. On 11 June 2015, Milan announced Abate had signed a contract extension to keep him at the club until 2019.
Abate played as a regularly starting right-back in the 2015–16 season. One notable moment for him occurred on 22 February 2016, when he made an excellent sliding tackle on Lorenzo Insigne on the right wing, preventing him from scoring a second goal in a 1–1 away draw against Napoli.
In late March 2017, after initially being sidelined for Milan’s following fixtures against Chievo, Juventus, and Genoa, Ignazio Abate was ruled out for the remainder of the 2016–17 season, due to requiring surgery after suffering “blunt force trauma” to his left eye, after being hit by a ball in the face during a match against Sassuolo on 26 February.
In late 2018, Abate temporarily assumed the role of a center back in the wake of an unexpected severe injury crisis that struck the team’s defense. He was praised for his performances by the coach Gennaro Gattuso and various Italian media outlets alike.
In the season 2018 / 2019 Iganzio Abate proved to be big professional. Even though his contact was set to expire, he played every match on high level. Most of the fans were impressed by his displays and his attitude.
Iganzio left AC Milan in July 2019, after his contract with AC Milan expired. At this moment he is still free agent.