During the following season, Harrison gradually established himself in the team on the left wing, making 15 league appearances with five goals, generally replacing Joe Turner.
Despite making only thirteen appearances he finished the season as top scorer with 17 goals, as Southampton again claimed the Southern League championship.
As a result of his goal-scoring prowess in the Southern League he was given an international trial by England (which was unsuccessful as he was played in an unfamiliar position)[2] and was by now being chased by several leading clubs in the north.
By now Southampton were beginning to struggle both on the pitch and financially and in November 1907, along with Fred Mouncher, he was sold to Fulham for a combined fee of £1,000.
In the FA Cup, Harrison was part of the West Ham team that defeated Middlesbrough of the First Division in the Second Round in February 1912.