Ferguson was born in Coalburn, South Lanarkshire, the younger brother of Willie Ferguson, who went on to play for Chelsea and play for and manage Queen of the South.[3] Like his brother, Pearson began his football career with Kello Rovers,[1] the junior team local to the family home in Kirkconnel, Dumfries and Galloway.[3] He moved on to Ayr United, and was playing for that club in the First Division in the 1929–30 season.[4]
He moved to Ireland in the 1931 close season to join Cork.[5] He scored in the opening match of the season as Cork came back from two goals down to secure a 3–3 draw away to Dolphin,[6] scored in the next match, a 2–2 draw with Shamrock Rovers,[7] scored twice in the third, a 6–0 demolition of Jacobs,[8] and in the fifth, exploited his pace to contribute four goals to a 5–3 defeat of Waterford.[9] He finished the 22-game season with 21 goals, which made him the League of Ireland's top scorer (jointly with Waterford's Jack Forster) and helped his club finish runners-up to Shamrock Rovers.[11]
Like most of the "cross-Channel" players who had played in Ireland that season,[12] Ferguson returned home, where he rejoined Ayr United.[1] He then played five times for Queen of the South in the second half of the 1932–33 season,[3] before moving south of the border to join Carlisle United of the Third Division North.[1] In the second of his two seasons in England, he was Carlisle's leading scorer, but with only eleven goals as they finished bottom of the league.[13]
Ferguson then returned to Scotland and spent four more seasons in the second division: two with Morton (plus one appearance in the top tier at the start of a third after helping them to promotion in the 1936–37 season) before moving on to Montrose then East Stirlingshire for a year apiece.[14]