Clark McConaghy often known simply as Mac, was a New Zealand professional player of English billiards and snooker.
McConachy was born at Glenorchy in Otago in 1895.He was the New Zealand professional billiards champion from 1914 until 1980. He also held the title of World Professional Billiards Champion from 1951 until 1968, when he was defeated by Rex Williams.

He was the runner-up in the World Snooker Championships of 1932 and 1952. McConachy scored one of the early snooker maximum breaks.