After a brief spell with A. Goldberg & Son, he was appointed in 1971 as a research and information officer with the North East Scotland Development Agency.

He contested the Parliamentary seat of North Angus and Mearns for the Liberal Party at the October 1974 general election, but the sitting Conservative and Unionist MP Alick Buchanan-Smith won with a majority of 2,551.

Bruce was elected as the Vice-Chairman of the Scottish Liberal Party in 1975, in the same year he became a director with the Noroil Publishing House.

He again stood for Parliament at the 1979 general election for the seat of West Aberdeenshire and was again defeated by the sitting Conservative and Unionist MP, this time Russell Fairgrieve by 2,766 votes.

Bruce stood for parliament for a third time at the newly created seat of Gordon, based largely on the former Aberdeenshire West.

[6] When he was elected to parliament, Bruce served on the Scottish Affairs Select committee, and in 1986 was given a job by David Steel as a Spokesman on Energy and Scotland.

[9] He was announced as a life peer in the 2015 Dissolution Honours and was created Baron Bruce of Bennachie, of Torphins in the County of Aberdeen on 19 October.

Bruce married secondly, in 1998, Rosemary Vetterlein, a Lib Dem activist and prospective parliamentary candidate[11] who contested Beckenham unsuccessfully in 1997.