He became a partner in the firm of Phyn, Ellices and Inglis, which had become interested in the XY Company in Canada.

He became a partner in the North West Company, and during the struggle with Lord Selkirk he played an important part.

He was Secretary at War from 1832 to 1834, during which time he proposed that appointments in the army should be made directly from his office.

Ellice was a co-owner of eight sugar estates in Grenada, British Guiana, Tobago and Antigua.

Ellice acquired the large Scottish Highlands sporting estates of Invergarry, with David Bryce building Invergarry House for him, in 1866 to 1869[6] and of Glenquoich further inland, where he entertained up to a thousand guests a year,[7] notable visitors including Sir Edwin Landseer, William Gladstone and Sir Henry Holland.

In 1859 his son's wife, Katherine Ellice served as host when the artist Richard Doyle visited and she was given an illustrated diary of a journey to the islands of Rona and Skye.

[8] His brother General Robert Ellice married Eliza Courtney; one of their grandsons became his son's heir in 1880.