After stepping out the pro-youth system for several years to play for local boys club Bathgate Rose, Ferguson signed with Airdrie on 15 August 2013. He originally formed part of the club's youth team before making his first team debut, aged just 17, on the last day of the 2014–2015 season against Dunfermline at the Excelsior Stadium. Although considered back-up to then Airdrie stopper Neil Parry in the 2015–2016 season, his reputation was growing and on the eve of Airdrie's Scottish Cup Fourth Round tie with Dundee United in January 2016, the Tannadice club launched a bid for the player, rejected by the Diamonds. They had a further bid rejected before another of Ferguson's former clubs, Hearts, showed interest. He spent some time on trial with then Airdrie boss Eddie Wolecki Black saying: “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.” He penned a new two-year deal as Airdrie turned full-time and, with Parry no longer at the club, Ferguson blossomed after being given the nod as the 'number one' for the 2016–2017 campaign, even winning the League One player of the month award for November 2016. He completed the season with the Diamonds having played 45 matches but couldn't help his side to promotion after they lost to Alloa in the League 1 / Championship Play-offsSemi Final.
On Friday 18 August 2017, Ferguson joined Motherwell on a three-year contract, but 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 to Airdrie on loan as part of the deal. Although yet to play a first-team game, Ferguson's first competitive game in Motherwell colours came in the Scottish Challenge Cup when he lined up for the Colts team against East Stirlingshire at the Falkirk Stadium. Ferguson made his first-team debut on 3 April 2019, coming on as a substitute for the injured Mark Gillespie in a 3–1 defeat away to Aberdeen. On 31 May 2020, Ferguson was released by Motherwell.
Airdrieonians (loan)
Following his move to Motherwell, Ferguson was quickly back at the Excelsior Stadium. He played a further 24 matches whilst on loan, taking his total appearances for the Diamonds to 80.
