18 year old Moroccan born striker Gassan Ahmade joined Norwich City on 29th January 2019 from Spanish amateur side Gimnastic de Manresa, who play in Group Three of the División de Honor Juvenil, the top level of Spanish football’s under-18 league system. Gimnastic compete against youth teams from the likes of Barcelona, Mallorca, Zaragoza and Girona, with Gassan the league’s top scorer last season with 10 goals.

He had spent some time with Norwich on trial in December 2018/January 2019. Supposedly Norwich beat off interest from a number of top European sides for his signature. He will initially train and play with Norwich's Under-18 and Under-23 sides.

During 2019/20 Ahadme played 16 times in all competitions for City’s under-23s, scoring six goals and registering one assist

On 29th July 2020 Gassan returned to Spain to join second tier side Real Oviedo on loan for the 2020/21 season. A nasty foot injury limited him to six appearances.

After playing on trial for Portsmouth in a pre-season friendly on 10th July 2021 and coming on as a substitute and scoring a hat-trick, he joined Pompey officially on a season-long loan on 20th July 2021. He had also scored twice in a pre-season friendly against Bristol City. Portsmouth boss Danny Cowley said “We’ve seen a lot of Gassan for Norwich U23s – and we liked what we saw. But we wanted to have a closer look at him with our own eyes and he’s been excellent for us in training. We called him ‘Trialist H’ at Havant & Waterlooville – which made him sound like he was from Line of Duty – but he scored three goals for us. He’s a clean finisher and got a couple more in the match we organised at St George’s Park on Friday and then another two at Bristol City. Gassan got a really good loan move to Real Oviedo last season. Unfortunately, he picked up a nasty foot infection, but has recovered from that now. He brings other people into the game and his movement is incredibly intelligent. He’s really good at finding his own space. I look at the guys in our squad and we need a link player like him at the top end of the pitch to combine with our other forwards. We’re really pleased to add him to the group and he certainly provides a different option to what we already have, while giving us tactical flexibility.”

On 14th January 2022 his loan with Portsmouth was cut short and he transferred to Burton Albion for an undisclosed fee. "He fits the profile of what we're looking for in a forward - he's mobile and has potential," said Brewers boss Jimmy Floyd Hasselbaink."We think we can develop him and make him a better player. We like that he plays with energy and can get around the pitch for a big forward." He had scored once in ten games for Portsmouth.

After scoring six goals in 20 League One appearances for Burton, he was signed by Ipswich on 1st September 2022 for an undisclosed fee. He signed a three year deal.

On 31st January 2023 he returned to Burton on loan having scored just one goal in eight games for Ipswich. He scored once for Burton in seven appearances.

On 27th June 2023 he was loaned to Cambridge United on a season long loan. He made 33 appearances scoring 13 goals.

He transferred to Charlton Athletic for an undisclosed fee on 4th July 2024, signing a four year contract. He was described by Charlton manager Nathan Jones as the club's number one target.