Mark is a product of the Club’s Academy and made his first-team debut under Neil Warnock in a 2017 FA Cup clash with Fulham.
Considered as one of the Bluebirds’ most promising young prospects, he made two further appearances in the league – one of which was against Huddersfield Town in the final game of the 2016/17 season.
Mark is a Wales youth international, who spent the first half of the 2018/19 season with League Two side Newport County before, in January, joining Port Vale on loan for the remainder of the campaign. At the beginning of the 2019/20 season, Mark joined Wrexham on loan for the entire campaign. He continues to be a key player for Wales at U21 level.
Since returning from his loan spell at Wrexham, Harris has scored three goals in six appearances as of March 1st 2020.