 He was educated at the University of Melbourne graduating on 14 August 1971 with the Degree of Bachelor of Arts  and then the Victorian College of Pharmacy, becoming a pharmacist.In 1972, he was elected to the Australian House of Representatives as the Labor member for La Trobe.As a backbench Member in 1973 Lamb, together with fellow Labor Member David McKenzie, introduced the Medical Practice Clarification Bill which, if passed, would have allowed abortion in the Australian Capital Territory.