Reginald McKenna was born in 1863. Educated privately and at Trinity Hall, Cambridge, he obtained a degree in mathematics in 1885.

A member of the Liberal Party, McKenna won North Monmouthshire in the 1895 General Election. In the government formed by Henry Campbell-Bannerman in 1905, McKenna was appointed as Secretary to the Treasury. This was followed by a year as President of the Board of Education (February 1907 - April, 1908). McKenna also served as First Lord of the Admiralty (1908-1911), Home Secretary (1911-1915) and Chancellor of the Exchequer (1915 - 1916) under Herbert Asquith.

McKenna was totally opposed to conscription and left the government after it was introduced by David Lloyd George in 1916. Like most Liberals that stayed loyal to Asquith, McKenna lost his seat in the 1918 General Election. After the election McKenna became Chairman of the Midland Bank and retired from public life.

Reginald McKenna died in 1943.