Moss Evans was born in a small terraced house in the Welsh village of Cefn Coed near Merthyr Tydfil. When he was 12, his family moved to Small Heath, Birmingham, as his father had heard there was work which he was determined to find. This was towards the end of The Depression and his father, a coal miner, had been out of work for 14 years.[citation needed]
Evans first became involved with trade unions whilst working for the Joseph Lucas combine, where he joined the Amalgamated Engineering Union in 1940 at the age of 15. His long involvement with the Transport and General Workers Union (TGWU) started ten years later when he changed jobs, and moved to the Bakelite factory in Birmingham, where he became shop steward a year later. His rise through the organisation of the TGWU started in 1956 when he became engineering and chemical officer for the Birmingham East district.[citation needed]