He is the son of Bryan Martyn, who also played for North Melbourne, and is a relative of early Carlton champion Paddy O'Brien.
He notched up his first league game against Geelong but did not come on until the third quarter, where he lined up on Gary Ablett Sr.
In 1995, he was awarded the Michael Tuck Medal after the Kangaroos beat the Adelaide Crows in the 1995 Ansett Cup.
[1][2] Martyn was injured in the 2002 Bali bombings, where he received burns to the back of his scalp.
However, that turned out to be his last match; he announced his retirement after the serious knee injury he suffered the next week at training.