Rev Hughes was a Presbyterian minister who became Moderator of the General Assembly in 1936, and was a lyric poet, hymn writer, and philosopher.

[5][3] He was elected to the House of Commons at an unopposed by-election in 1941, as Member of Parliament for Carmarthen, following the resignation of Labour MP Major Daniel Hopkin MC.

A block of flats in Hilldrop Crescent, Holloway, in Islington North, is named Moelwyn Hughes Court.

In March 1946 33 people were killed and hundreds injured at the Burnden Park grounds of Bolton Wanderers football club, who were playing Stoke City in an FA Cup match.

Ronw's wife Louise Mary, eldest daughter of the judge Arthur Greer, 1st Baron Fairfield, survived him on his death in 1955 at the age of 58.