Iwobi joined Arsenal while still at primary school, in 2004, and was nearly released by the club at the age of 14 and again at the age of 16.

He was first involved in a first-team match as an unused substitute in a League Cup match against West Bromwich Albion on 25 September 2013.
He signed a long-term contract with Arsenal in October 2015.

On 27 October 2015, Iwobi made his first-team debut for the club, starting in a 3–0 defeat to Sheffield Wednesday in the Round of 16 of the League Cup.
He made his Premier League debut four days later in a 3–0 win against Swansea City at the Liberty Stadium, as a stoppage time substitute for Mesut Özil.
Iwobi made his Champions League debut as an 85th-minute substitute in a 5–1 defeat against Bayern Munich.
Iwobi started in the first team for the 2015–16 FA Cup 3rd and 4th round home wins against Sunderland and Burnley respectively.

After getting a first Champions League start in a 3–1 away defeat to Barcelona, Iwobi went on to score two goals in his first two Premier League starts in wins against Everton, and Watford, respectively.

In the following season, Iwobi changed his squad number from 45 to 17, after Alexis Sánchez took number 7 from the departing Tomáš Rosický.
He went on to feature throughout Arsenal's victorious FA Cup campaign of 2016–17, winning 2–1 against Chelsea in the final.
He achieved further success with Arsenal in the 2017 Community Shield, in which Arsenal beat Chelsea on penalties.

In January 2018, a video was released that allegedly showed Iwobi at a late-night party 36 hours before a match.
In May 2018, after Arsenal manager Arsène Wenger announced he would be leaving the club, Iwobi described him as an "inspiration" and stated it was sad but exciting.

In August 2018, he signed a new long-term contract with the club, reportedly until 2023.

In January 2019, Iwobi was the subject of alleged racism from Indian actress Esha Gupta, an Arsenal ambassador.
In July 2019, after the 2019 Africa Cup of Nations, he said he was looking forward to returning to club football with Arsenal.
Iwobi joined Arsenal while still at primary school, in 2004, and was nearly released by the club at the age of 14 and again at the age of 16.
He was first involved in a first-team match as an unused substitute in a League Cup match against West Bromwich Albion on 25 September 2013. He signed a long-term contract with Arsenal in October 2015.
On 27 October 2015, Iwobi made his first-team debut for the club, starting in a 3–0 defeat to Sheffield Wednesday in the Round of 16 of the League Cup. He made his Premier League debut four days later in a 3–0 win against Swansea City at the Liberty Stadium, as a stoppage time substitute for Mesut Özil. Iwobi made his Champions League debut as an 85th-minute substitute in a 5–1 defeat against Bayern Munich. Iwobi started in the first team for the 2015–16 FA Cup 3rd and 4th round home wins against Sunderland and Burnley respectively.
After getting a first Champions League start in a 3–1 away defeat to Barcelona, Iwobi went on to score two goals in his first two Premier League starts in wins against Everton, and Watford, respectively.
In the following season, Iwobi changed his squad number from 45 to 17, after Alexis Sánchez took number 7 from the departing Tomáš Rosický. He went on to feature throughout Arsenal's victorious FA Cup campaign of 2016–17, winning 2–1 against Chelsea in the final. He achieved further success with Arsenal in the 2017 Community Shield, in which Arsenal beat Chelsea on penalties.
In January 2018, a video was released that allegedly showed Iwobi at a late-night party 36 hours before a match. In May 2018, after Arsenal manager Arsène Wenger announced he would be leaving the club, Iwobi described him as an "inspiration" and stated it was sad but exciting.
In August 2018, he signed a new long-term contract with the club, reportedly until 2023.
In January 2019, Iwobi was the subject of alleged racism from Indian actress Esha Gupta, an Arsenal ambassador. In July 2019, after the 2019 Africa Cup of Nations, he said he was looking forward to returning to club football with Arsenal.
Alex Iwobi