Fraser was born into a Presbyterian family in Inverness. He moved to Berwickshire with his family as a child. In 1931, he entered the University of Edinburgh to study Technical Chemistry. He also became a member of the Young Communist League He joined the International Brigades on the outbreak of the Spanish Civil War in 1936, and was the only British member of the International Brigades to serve as an officer with the Servicio de Información Militar, the secret service of the Spanish Republican Armed Forces. Following the end of the conflict, he returned to Scotland and became a Communist Party of Great Britain group leader at the John Brown & Company Engine and Boiler Works at Clydebank. He authored a successful pamphlet defending the party's position on the Second World War, The Intelligent Socialist's Guide to World War II, and was subsequently appointed Scottish Propaganda Secretary of the Communist Party of Great Britain. He became increasingly unhappy with the party in the mid-1940s, leaving the party in 1945.
Following his resignation, Fraser enrolled in Jordanhill College of Education, becoming a primary school teacher in Ayrshire after his graduation. During his time at Jordanhill, he received religious instruction from a Jesuit priest and converted to Catholicism in 1948. He abandoned Marxism and became an outspoken anti-communist, campaigning against the Communist Party of Great Britain MP Willie Gallacher in the West Fife constituency in the 1950 UK general election. Gallacher later attributed the loss of his seat in the election to the opposition of Fraser and other Catholic anti-communists. Fraser helped to introduce the Blue Army of Our Lady of Fátima, an international lay Catholic and anti-communist organisation, to Scotland. In marked contrast to his earlier membership of the International Brigades, Fraser supported the reintegration of Francisco Franco's Spain into the international community in the post-Second World War period. He applauded 'the heroic stand of General Franco against Soviet barbarism' in a speech in Dublin in the early 1950s. He argued that the political repression of the Servicio de Información Militar during the Spanish Civil War presaged state repression in the Eastern Bloc during the early Cold War. In 1954, Fraser published Fatal Star, an account of his journey from communism to Catholicism. In 1956, he led protests in opposition to a visit to Britain by the Soviet statesmen Nikita Khrushchev and Nikolai Bulganin.
Fraser was critical of the liberalising reforms of the Second Vatican Council and of the contemporaneous emergence of liberation theology in Latin America. In 1965, he left his teaching position to devote himself full-time to his periodical Approaches. The publication reflected Fraser's traditionalist Catholic views and his uneasiness about the changes within the Catholic Church in the 1960s. In the 1970s, Fraser served as a Scottish Conservativecouncillor in the town of Saltcoats, Ayrshire. He died on 17 October 1986 and was survived by his wife, Kathleen, and his seven children. His son Anthony Fraser edited the Catholic magazine Apropos, a successor of Approaches, until his death in 2014.
