Isaak joined the club at the age of seven and has enjoyed a number of impressive seasons in front of goal for the U18 and U23 sides. 

He featured on the First Team bench on a number of occasions in 2020/21 and was part of the Bluebirds' 2021/22 pre-season campaign.

Isaak's competitive First Team debut was against Middlesbrough in October 2021. His first senior goal came in the Emirates FA Cup against Preston North End in January 2022.

The Wales U21 international spent the 2023/24 season on loan with KV Kortrijk in Belgium.