Career
Marsden was made a Royal Navy Sub-lieutenant on 15 November 1902 and was promoted to Lieutenant on 31 August 1904. He later was promoted to Lieutenant Commander, and as such was in command of the Acasta-class destroyer HMS Ardent in 1916 at the Battle of Jutland. The Nassau-class battleship SMS Westfalen sank Ardent, but Marsden was commended for his service in the battle.
Later Marsden was promoted to Captain, and on 5 October 1920 he transferred to the Royal Navy Retired List.
Marsden first stood for election to the House of Commons at the 1929 general election, when he unsuccessfully contested the Communist-held Northern division of Battersea. He held the seat until he retired from the Commons at the 1950 general election.