For eight seasons (1959–1966) Motley captained the then dominating team of the League, including a stint as captain-coach from 1959 to 1961. He was the only man to appear in all nine of the Magpies premiership teams between 1954 and 1965. Motley played a total of 258 games for Port between 1953 and 1966 and also represented South Australia on 28 occasions. 
During his career, Motley was never dropped from the league team and was never reported. During his time in league football, not being reported for foul play was a rare thing for a player as at the time having a certain amount of mongrel or thuggery was seen a common thing.
Motley was named Port Adelaide's best and fairest player in 1958, 1959, 1963, and 1965; and won the Magarey Medal in 1964. 
Motley was captain-coach of the Magpies 1959 premiership winning side. He later went on to coach North Adelaide in 1967-1969, taking the club to 3rd, 3rd, and 5th.
Since retiring, Motley has been bestowed with several honours including life membership of Port Adelaide and the SANFL, and membership of the South Australian Football Hall of Fame and the AFL Hall of Fame. In 2001 Motley was named on a half-back flank in Port Adelaide's 'Greatest Team of All Time'.
Note: "Geof" is the correct spelling of his name.