Spotted playing in local parks football with Southampton Cambridge, John Cotton joined the Saints as an amateur and immediately had a run-out in the Western League. Impressive performances at left-back for the Reserves soon earned him a pro contract but he was released at the end of the season, without ever returning to the first team. John had to settle for Hampshire League football, with Salisbury and Winchester, in turn.

He was of an age to volunteer for service in the First World War or to be conscripted after 1916. But he is in a minority of Saints of that era for whom the club historians and their research associates have been unable to find any details of what they did, whether militarily or at home, in 1914-19.