Tompkins was a partner in the Hamilton legal firm of
Tompkins Wake from 1953 to 1971 and continued practising as a barrister until 1983. He was appointed
Queen's Counsel in 1974 and served as a judge of the Courts Martial Appeal Court between 1982 and 1983. In 1983, he was appointed to the bench of the High Court, serving as a judge until 1997, although he continued to serve after that as an acting judge. Between 1989 and 1992, he was executive judge of the High Court in
Auckland, from 1995 he was a judge of the Court of Appeal of Tonga, and from 1997 a judge of the Court of Appeal of Fiji. ==Honours and awards==