In April 1892 Crampton joined the Slaughtermen's Union in April 1892, beginning a lifelong association with the union movement. He moved to Queensland in 1898 and was working as a meatworker in northern Queensland where he became concerned about the conditions of working men. In particular, he was concerned that many abattoirs would only employ workers on contracts that gave them no job security. In 1904, he had moved to Brisbane and became the full-time organizer for the Australasian Federated Butchers' Employees' Union in 1908. In this role, he worked tirelessly to unionise the abattoirs of North Queensland. When managers would turn him away from their premises, he would slog through mud flats and bush to find a back entrance to the workplaces to talk with the workers. Crampton sought to achieve greater unionisation in all workplaces. From 1910 to 1913, he was a member of the central political executive of the Australian Labor Federation. In 1911 he established the southern district branch of the Amalgamated Workers' Association and was involved in organising the sugar workers' strike at Mackay, Queensland. In 1912, he became President of the Brisbane branch of the Australian Labor Federation. In 1912, Crampton stood for election as a member of the Labor for the Legislative Assembly of Queensland for the seat of Windsor, but was not successful. Instead he became secretary of the Queensland branch of Australasian Federated Butchers' Employees' Union. He was a director of the newspapers The Daily Standard and The Worker, both of which were affiliated with the Australian Labour Party. In 1914, he resigned his roles with his union to work as a journalist on The Daily Standard, writing under the name Jack Aster. In 1915–17 he was appointed to the public service as the director of labour, where he worked to reorganise the department. In 1917 he returned to the Daily Standard as its general manager, a role he held until 1927. In 1916-19 Crampton was a government representative on the Senate of the University of Queensland. Jack Crampton was a member of Labor and was appointed to the Queensland Legislative Council on 10 October 1917. Although it was a lifetime appointment, the Council was abolished on 23 March 1922. Jack Crampton was one of those who voted for its abolition, as it had been Labor Party policy to abolish the Council for many years. Crampton was an alderman of Brisbane City Council from 1921 to 1925 and then again from 1934 to 1937 in the Paddington Ward and from 1937 to his death in 1938 in the Baroona Ward. During this time, he served on the following committees:.
