Ferguson formed part of the Diamonds youth team before making his first-team debut, at the age of seventeen, on the last day of the 2014-15 season versus Dunfermline at the Excelsior Stadium.[1] Although considered back-up keeper to Airdrie's number one keeper Neil Parry in the 2015-16 season, his reputation was growing and on the eve of the DiamondsScottish Cup 4th round match with Dundee United in January 2016, the Tannadice club launched a bid for the player that was rejected by the Diamonds.[2]
The Terrors had a further bid rejected before another of Ferguson's former clubs, Hearts showed interest, as Ferguson spent time on trial with the Tynecastle club, as Airdrie's manager Eddie Wolecki Black said: "Rohan is recognised now as one of the hottest young prospects in the game. He sparkled in our recent 1–0 Scottish Cup defeat by Dundee United and relished the experience of training with Hearts. We will need to see what develops in the months to come."[3]
Ferguson then signed a new two-year contract, as Airdrie turned full-time and with Parry no longer at the club, Ferguson was the new number one keeper for the 2016-17 season, as he won the League One player of the month award for November 2016.[4] Fergsuon completed the season with the Diamonds having played 45 matches but couldn't help his club to promotion after they lost to Alloa in the play-off semi final.[5]
Motherwell
On Friday 18 August 2017, Ferguson signed for Motherwell on a three-year contract, although he was immediately sent back out on loan to Airdrie for the remainder of the 2017–2018 season. Youngsters Jake Hastie and Luke Watt were also sent out on loan to Airdrie as part of the deal.[6] Ferguson played a further 24 matches for Airdrie on loan and ended up with 80 appearances for the Diamonds.
On 8 June 2021, Ferguson signed a one-year deal with NIFL Premiership club Larne.[12] He helped Larne to become the first Irish Football League team to qualify for the Europa Conference League in the 2024/25 season, after beating Lincoln Red Imps on aggregate.