Bob Watson brought a considerable amount of experience to St James’ Park when he joined Exeter City ahead of the first season in the Southern League. Arriving from Leeds City, together with Fred Parnell, he captained the side in the club’s first professional game in September 1908. Having earlier appeared for Middlesbrough and Woolwich Arsenal, he remained with the Grecians for four seasons before joining Stalybridge Celtic.    

Having appeared for nearby South Bank, a strong amateur team of the time, he signed for Middlesbrough in 1901 and made 16 league appearances (5 goals) ahead of joining Woolwich Arsenal in 1903 prior to moving on for a three-stint with Leeds City between 1905 and 1908.

Having had 83 league outings (and scoring twenty-one times in the process) for the Yorkshire club, Bob would have been an important signing when he joined the newly-professionalised Exeter City in 1908. Arriving with Leeds City teammate Fred Parnell, he made his City debut as captain in the club’s first-ever Southern League game against Millwall on 2 September 1908 and soon afterwards featured in the club's inaugural FA Cup tie against Weymouth on 3 October 1908.

Becoming a regular member of the side, he played in starting with the club's first-ever game in the competition against Weymouth on 3 October 1908 of the Grecians’ eighty league games during his first two seasons with the club before playing less often in 1910/11 (24 appearances). Featuring 34 times in the following season, he left St James’ Park in the summer of 1912 after making 137 league appearances as a mainstay of the club’s early professional years. Having also contributed an important 25 goals during his four-year stay, Bob moved on to Stalybridge Celtic before playing for Rochdale, South Liverpool and Chorley in the run-up to the outbreak of war. 

Bob also enjoyed a fine FA Cup scoring record during his time with Exeter scoring eight times in the club's first cup campaign - including a hat trick against Longfleet St Mary - and goals in other seasons against Nunhead, Stoke and Nelson.