He appeared in 41 first-class matches as a right-handed batsman. Mills was born in Kettering on 6 December 1958 and is the son of Michael Mills, who played for Cambridge University and Warwickshire after the Second World War. Peter Mills scored 1,585 runs with a highest score of 111.
He bowled just one over of right-arm medium pace in first-class cricket.
He played Minor Counties cricket for Cambridgeshire between 1980 and 1984.