Michael Alan Harmel was born to Irish immigrant parents in February 1915 in Johannesburg. He was an intellectual and revolutionary and became a radical socialist opposed to racism while studying at Rhodes University in the 1930s. After graduating from Rhodes with an MA in English literature, Harmel worked in London for the British Communist Party's newspaper The Daily Worker. He returned to South Africa in 1939, and immediately joined the Communist Party of South Africa. At the early age of 25 he was elected to the Johannesburg District Committee where he served as a District Secretary. After the dissolution of the Communist Party in 1950 Harmel worked tirelessly towards reconstitution of the Party and was a prominent member of the underground Party collective. Publicly he devoted most of his time to journalism. He was on the editorial board of Liberation, and also worked as a correspondent of The Guardian, Spark and New Age. Harmel also collaborated in the formation of the South African Congress of Trades Unions (SACTU) and was a founder member of the Congress of Democrats. He was one of the first to be banned under the Suppression of Communism Act which he defied and for which he was arrested. In 1959 Harmel became the first editor of the Communist Party's new journal, The African Communist". He wrote countless articles for that journal, largely under his pseudonym, A. Lerumo. He was also one of the commanders of Umkhonto we Sizwe. While tutoring in Marxism-Leninism to new recruits of the Communist Party, he played a leading role in drafting this Party's new programme.

In 1962 Michael Harmel was one of the first people to be placed under 24 hour house arrest for 5 years. Subjected to repeated state harassment he was instructed by the Communist Party to go into exile in London where he continued editing and producing The African Communist. While in exile, Michael Harmel continued his full-time work in both the MK and the Communist Party. He also played an important role in the shaping and work of the British Anti-Apartheid Movement, as well as the establishment of the Irish Anti-Apartheid Movement. On the occasion of the 50th anniversary of the Communist Party Harmel wrote a book containing the history of this party and entitled: "Fifty Fighting Years". It was published under his pseudonym A. Lerumo and translated into many languages.

Michael Harmel was sent to Prague to become the Communist Party's representative to the journal World Marxist Review. He worked and lived in Prague with his wife and daughter until his death at the age of 59 on 18 June 1974. He was survived by his wife Ray Harmel (1905-1998), his daughter Barbara, and his granddaughter Lisa.