Lumsden moved from Kurri Kurri in 1955 to play with Sydney's Manly-Warringah club. After just four games he was ruled ineligible on the grounds he didn't reside in the area.
In 1956 Lumsden represented for Country seconds and while playing for Country he was seen by St. George. He was offered £300 and a job with the water board. In his debut Sydney season in 1957 represented for both Sydney firsts and New South Wales in 1957.
He was the competition's leading try scorer in 1958 (18 tries) and 1962 (21 tries). He was the second post-war player after Ian Moir to score a century of tries. He gained selection in the Australia national team, becoming Kangaroo No. 346. On the 1959-60 Kangaroo tour he played in all six Tests and 21 minor tour matches scoring 25 tries in total, topping both the try-scoring list and tally for most matches played by an Australian on the tour. Becoming a regular selection for Australia, he played against France in 1961; Great Britain in the 1962 Ashes series; New Zealand New Zealand in 1963; with his last Test appearance against South Africa in 1963. He reached this milestone in his 100th game during the 1963 season.
He retired from the game after the Dragons' eleventh consecutive premiership in 1966.
After working as a wine merchant Lumsden enjoyed business success managing, then buying and selling hotels. He was awarded Life Membership of the St. George Dragons in 1969.  Lumsden became a rugby league selector in 1977 for Country and NSW, spending 23 years in the position, and 14 years as an Australian selector.