A partner in a Birmingham mercantile firm (1864–79), Collings served as mayor of the city (1878–80), succeeding Joseph Chamberlain, with whose municipal reform program he had been closely associated. Subsequently he was a member of the House of Commons (1880–1918), parliamentary secretary to the Local Government Board (1886), and under secretary to the Home Office (1895–1902).

In 1869 Collings became secretary of the National Education League, an influential body that advocated free, nondenominational elementary schools. Later he helped to found the Rural Labourers' League and was a trustee of Joseph Arch's National Agricultural Labourers' Union. Collings urged workers' participation in ownership of farmland and vocational education in agricultural areas. In 1884 he was appointed a member of the important Royal Commission on Housing. The Land Settlement Act of 1919 incorporated many of his ideas.

On Jan. 27, 1886, Collings caused the fall of the Conservative government of Lord Salisbury by introducing, as an amendment to an Irish coercion bill, a measure in favour of English rural smallholdings. The following March he resigned as Local Government Board secretary (along with Chamberlain, at that time board president) in protest against the Irish Home Rule proposal of Salisbury's Liberal successor, William Ewart Gladstone.