On 30th June 2018, it was announced that centre-half Andrew Omobamidele had signed a contract to be an Academy Scholar, playing for the Under-18s. He was previously with Irish side Leixlip United. whom he joined as an Under-9. The softly spoken centre back was described as an 'introvert' by long time coach and mentor Kenny Molloy who nurtured the youngster's talent from the point he first arrived at the club as a wide eyed nine-year-old. When he joined the Irish club, there was a period of frustration for the youngster as he was told to train with the B team whilst the majority of his friends were placed in the club's A team set up.That frustration was used as fuel to improve and Omobamidele was often seen hopping the fence at Leixlip to get onto the pitch so he could continue his development after most had elected to go home for the day. 

Before joining Norwich, he trialled with Leeds, Rotherham and Stoke. He was also watched by Manchester United scout Larry Dunne. One club struck a mutual agreement with Omobamidele, before reversing on that decision at the last minute. After an increased effort to get Omobamidele a move to England, Norwich came calling after being impressed with his performances in two cup competitions. Former coach Kenny Molloy said "But at that stage he was starting to fill out his boots and developing more physically. He then got interest [after playing] in the Milk and Galway Cup. He then went over to Norwich and did okay in the first trial and then he did a little bit better in his next one." After spotting his considerable potential, Norwich decided to offer him a professional deal despite a 6-0 defeat to Chelsea in an academy match. 

In March 2019, he played the full 90 minutes for Ireland's Under-17s in a 2-1 defeat to Finland

He was called up to the Republic of Ireland Under-18s in September 2019 for a tournament in Sweden.

On 2nd December, he signed his first professional contract with Norwich. “It’s an amazing feeling, it’s what I came to England to do, work hard and try get my first professional contract and it’s came so I’m very excited, ready to go again. I definitely worked hard to be where I am. I don’t think age really matters, I think once you’re able to play at a level, age doesn’t change anything. I have been working really hard, trying to string performances together and all stuff surrounding that.”

Andrew was on the bench for Norwich in the Carabao (League) Cup first round clash at Luton on 5th September 2020 which Norwich lost 3-1. The Canaries had 15 first teamers missing due to international call-ups with a further two injured. However he was not utilised. Three days later he played as Norwich's Under-23s defeated Plymouth 3-2 at Home Park in the Football League Trophy.

Following the departures of fellow centre-backs Ben Godfrey and Timm Klose in early October 2020, it was reported that Norwich were considering fast-tracking Omobamidele to the first team. He didn't do his chances any harm when impressing in Norwich's Under-23s 5-0 thrashing of Newport County in the EFL Trophy on 6th October 2020, in which he captained the City side. Norwich's injury crisis in November 2020 saw Andrew on the bench for Norwich's clash with Coventry City on 28th November 2020.

He signed a new contract with Norwich on 23rd December 2020 which will extend his stay at Norwich to 2024 even though he hadn't played for the first team (but had been on the bench for eight games at the time of his signing).

He made his Norwich City debut as a late substitute in the 2-1 win at Cardiff City on 16th January 2021 in the Championship.

Omobamidele made his Republic of Ireland under-21 debut, at the age of 18, on 26th March 2021 in 2-1 win over Wales. Norwich teammate Sam Blair was on the substitute's bench.

He made a total of 9 appearances for City, including eight starts due to injury to Ben Gibson, as the Canaries won the Championship title.

On 24th May 2021 he was called up to the full Ireland squad after being named in Stephen Kenny’s squad for friendlies against Andorra and Hungary. However he didn't play in either match. Andrew finally made his international debut on 1st September 2021 coming on as substitute for Dara O'Shea in a game that saw Portugal come back from being 1-0 down to win 2-1 with Cristiano Ronaldo scoring twice. His full debut came on 7th September in a 1-1 draw over Serbia.

He made seven appearances in 2021/22 but scored his first senior goal in the 2-1 defeat to Leeds in the Premier League on 31st October 2022.

On 26th February 2023 the Sun on Sunday claimed that Notts Forest were watching Omobamidele, having scouted him. He has also been linked with Leicester. At the beginning of May 2023, The Telegraph suggested that AC Milan and Nice were interested in Omobamidele whom Norwich allegedly would be willing to sell to fund a rebuild of their squad. He was said to be valued at £22m.

He made 35 appearances for Norwich during the 2022/23 season, scoring once.

On 9th June 2023 he was linked with a move to newly promoted Premier League side Sheffield United. The Sheffield Star revealed United have made contact with tNorwich about a potential transfer deal for one of their players.. On 20th June 2023 it was reported that Crystal Palace were planning a swoop for Omobamidele as a potential replacement for Marc Guehi. A fee of £20m was suggested.

On 1st September 2023 he signed for Notts Forest for a fee reported to be £11million plus add-ons.

On 2nd January 2024 he was linked with a loan move to Daniel Farke's Leeds United.