He was educated at South Brisbane State School.
King trained as a solicitor articled to Alfred Glassford Unmack. Reginald King was elected to the Queensland Legislative Assembly in the electoral district of Logan at the 1920 election. He held the seat until 11 May 1935 (the 1935 election), when he was defeated because of the redistribution of the Logan electorate.
He was Secretary for Public Works and Public Instruction from 21 May 1929 to 17 June 1932.
In retirement, Reginald King was a keen gardener. Reginald King died on 7 September 1955 in Brisbane.
He was a Member of the Queensland Legislative Assembly. Reginald King was a member of the Coorparoo Shire Council from 1896 to 1927, being elected Chairman on 9 times from 1898. During this time, he was a member of the Nationalist Party, the Queensland United Party and the Country and Progressive National Party.