After leaving Christ Church school Bob became a plasterer by trade, while his interest in sport led him to join the George Salter's Spring Works football team, the West Bromwich Strollers.

He played in various positions, including full-back, half-back and forward, and there is record of him scoring against Smethwick Holy Trinity in February 1880 in a 3–0 victory.

However, he was generally not a success as an outfield player, one observer describing him thus:[4] As a forward he was useless, and as a half-back, or back, he could stop a man, but invariably missed the ball.Roberts kept goal for the first time during the 1880–81 season.

[4] In 1885 Albion reached the FA Cup quarter-final, but lost 2–0 to Blackburn Rovers; Roberts was unable to participate in the match due to "rheumatics".

[9] He was ever-present in that first league season of 1888–89, making 22 appearances and keeping four clean sheets (and kept the opposition to one-in-a-match on four separate occasions.

When Bob Roberts played as goalkeeper on 13 October 1888 against Preston North End he was 29 years 187 days old; that made him, on that sixth weekend of League football, West Bromwich Albion' oldest player.[7]).

[9] In May 1890 Roberts moved on a free transfer to Sunderland Albion; their offer of 50 shillings per game was one that West Bromwich were unable to match.

[4] He returned to West Bromwich Albion on another free transfer in May 1891, and was initially given his place back, at the expense of Joe Reader.

[11] He moved back to the North East, where he settled for the remainder of his life, working as a plasterer,[12] and died in Byker on 20 October 1929.