Elizabeth Macarthur-Onslow’s son, Major-General James William Macarthur-Onslow, had a notable career in three spheres – the army, in politics, and on the land. He was born at Camden Park and educated at the Sydney Grammar School, and Trinity College, Cambridge University, where he graduated B.A. and L.L.B. holding the Volunteer Decoration, the Chitral Campaign Medal, and the Queen’s South Africa Medal. In South Africa he commanded the 5th Battalion of the Australian Commonwealth Horse during 1902, and was on Major-General Sir Edward Hutton’s staff.

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Volunteering for service in World War I, he served as Transport Officer with the A.I.F. after receiving leave of absence as member for Bondi in the Legislative Assembly, and he returned to politics after two years. General Macarthur-Onslow was a member of the Legislative Assembly from 1907-22 and of the Legislative Council from 1922-23.

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In 1897 he married Enid, granddaughter of Hannibal Macarthur, and they had one son and two daughters. Despite his many activities General Macarthur-Onslow’s first and greatest characteristic was his love for the land. His hobby, he used to say, was gardening, but his knowledge of the problems affecting primary production was attested by the wide esteem given to his views on agricultural matters. On other matters, as well as these, he was outspoken and forthright at all times. His fearlessness in debate, part of his fighting spirit, was always at the service of what he believed to be the right course.

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He assumed occupancy of Camden Park in 1931 and lived there until his death in 1946.