The son of a coachbuilder, Lamb was educated to elementary level at state schools—including one at the oil shale mining village of Airly—and from the age of 12 he worked as a grocer's boy and then as a coalminer.

[5] Lamb succeeded Daniel Clyne as the Speaker of the New South Wales Legislative Assembly after the 1947 election and retained the position for twelve years.

His time as speaker was characterised by his singular interpretation of standing orders and firm control, leading to frequent criticism from the opposition for inflexibility, unnecessary interjections from the chair and bias towards the government.

Controversially he even opposed some of his government's legislation, including the Local Government (Areas) bill in 1948, calling it a "flagrant violation of the fundamental principles of the democratic system" which was a reference to the decision to amalgamate Granville Council into Parramatta instead of the other way round.

[12][13] Lamb retained his seat of Granville throughout his time in parliament but lost Labor Party pre-selection prior to the 1962 state election and retired.