In 1854, when Kitson was aged nineteen, his father bought the ironworks at Monk Bridge and put him and his elder brother, Frederick, in charge. Monkbridge was amalgamated with their father's Airedale Foundry in 1858. In 1886 the business was a limited liability company under family control with £250,000 in capital. Frederick Kitson withdrew from the business because of ill health several years before his death in 1877. Their father retired in 1876 but James Kitson in reality ran the firm from 1862. The Airedale Foundry built nearly 6,000 locomotives for use in Britain and abroad from when it was founded until the end of the 19th century. The company diversified into manufacturing stationary engines for agricultural use and steam engines for tramways. From the 1880s, the Monkbridge works made steel using the Siemens–Martin open-hearth process. The Airedale Foundry and Monkbridge Works both employed about 2000 workers in 1911. He was elected MP for Colne Valley from 1892 until 1907, supporting education,
Irish Home Rule, and the provision of
old age pensions. Kitson was a member of the
Institution of Civil Engineers and the
Institution of Mechanical Engineers. He supported the
Mechanics' Institute and the
Yorkshire College, the forerunner of the
University of Leeds, which awarded him an honorary doctorate,
DSc in 1904. Kitson was never a member of Leeds Council but was the city's first lord mayor in 1896–7. He was created a baronet in 1886 and was sworn of the
Privy Council in 1906. Kitson was appointed
Honorary Colonel of the 3rd (
Volunteer) Battalion,
The Prince of Wales's Own (West Yorkshire Regiment) on 20 December 1902. He was President of Manchester College, Oxford (now named
Harris Manchester College) from 1909 to 1911. ==Death==