Sebastian was another late starter, not beginning playing 'til the age of 12. The club was Canberra North, just one of a number of clubs to have been rolled into what is now the Majura Soccer club in the inner north of the ACT.
Sebastian, a proud and current Canberra, made the first of his 2 Australian appearances in 1978 against Greece, the other some 3 years later in the 3-3 draw against NZ.