Dean signed for Rovers in 2016 and was a regular goalscorer for the Under 17 and Under 19 sides. He made his first-team debut in September 2018 against Limerick at Tallaght Stadium. The following February, shortly after signing his first professional contract with Rovers, he went on loan to Athlone Town for the first half the 2019 season before another loan spell with Bray Wanderers in the summer transfer window. Between both clubs, he scored 18 goals in all competitions in 2019.
He returned to Rovers ahead of this season and scored his first competitive goal at home to Waterford in a 6-1 win. Rovers manager Stephen Bradley recently said that Dean reminds him of Robbie Keane at a similar age and regards him as one for the future.