In his youth, McKenna was a noted rower and was a member of the winning Cambridge crew in the 1887 Boat Race. In 1895 McKenna was elected Liberal MP for North Monmouthshire and represented the constituency until his defeat in the 1918 ‘Coupon Election’. He served in the Campbell-Bannerman and Asquith cabinets as President of the Board of Education, First Lord of the Admiralty and Home Secretary. In Asquith’s Coalition Government of 1915 he succeeded Lloyd George as Chancellor of the Exchequer. After he left Parliament, McKenna became Chairman of the Midland Bank in 1919, a post he held until his death in 1943.