Alnwick, Northumberland born goalkeeper Bob Hewitson began his football career with Morpeth Harriers in 1900 from where he signed for Second Division Barnsley in May 1903, making his Football League debut against Leicester Fosse that September, immediately becoming The Tykes’ regular keeper, being ever present between the sticks in his debut season as Barnsley finished 8th. The following season he retained the gloves before losing his place to Elijah Round in March. Although he returned for the last three matches of the season, he left Barnsley after 66 appearances in May 1905 to join Southern League Crystal Palace.
He played 75 matches for Palace over the next two seasons, helping them to win the Southern League Second Division Championship in his first season, before returning to Football League action when he signed for newly elected Second Division Oldham Athletic in August 1907, making 31 appearances during his single season at Boundary Park, keeping goal for them in their inaugural Football League fixture against Stoke a month later.
He then signed for newly elected Tottenham Hotspur in July 1908, keeping goal for them in their first Football League fixture in a 3-0 win over Wolverhampton Wanderers that September. Hewitson played 34 matches for Spurs as they won promotion to the top flight in their inaugural League season, finishing as Second Division runners up, before leaving the club to join Southern League Croydon Common in the 1909 close season. After 38 appearances for The Commoners during 1909-10 he joined Midland League Doncaster Rovers in the summer of 1910, and subsequently ended his career with them.