He joined the Falkirk Central Ironmoulders' Society, a very small union with only twelve members at the Carron Iron Works where he was based.
As a result, he was immediately chosen as its shop steward, and rapidly built up membership at the works until all five hundred workers had joined.
[1] Lyon again proved his organisational skills at the Carters' Association, gaining recognition from the Glasgow Corporation and leading successful strikes.
[1] Lyon believed that motor vehicles were a passing craze, and that the union should focus on recruiting workers who used horses and carts.
These problems, coupled with increasing periods of poor health, led to disagreements with other officials in his own union, and he was eventually dismissed as general secretary in 1936, to be succeeded by Robert Taylor.