Sharrock played most of his career as a half forward flanker and was a premiership player in his first season at Geelong, in 1963. Due to an injury to Roy West, he spent the first half of 1966 playing at fullback before moving to centre-half forward for the second half of the season. He had his best season, finishing third in the count.
In 1968 he suffered a career ending knee injury during an Inter-League game and despite having represented Victoria at interstate football earlier in the season it would be his last year in the game.
John was awarded a Life Membership with Geelong Football Club in 2012.