Robert is married to Fiona, and they have three daughters, Helen (five years old), Kirsty (two years old) and Elizabeth, born in February 2000. Before his election, Robert managed the family estate, near Chapel of Garioch, Aberdeenshire.

Robert was educated at Merchant Taylors' School, Northwood and Aberdeen University and has twice served as a member of Aberdeen University Court. His interests include hill walking and sailing.

Robert was elected Liberal Democrat MP for West Aberdeenshire and Kincardine in May 1997, defeating former Scottish Office Minister, George Kynoch. He had previously contested Aberdeen North in 1987 for the SDP/Liberal Alliance, coming second to Labour. He was elected to serve the Upper Donside ward of Aberdeenshire Council in April 1995, leaving the Council in June 1997 following his election to Parliament. Robert was the Vice Convener of the Grampian Joint Police Board during this period.

Robert Smith is Liberal Democrat Scottish Affairs Spokesman in the Commons, and a member of the Scottish Affairs Select Committee. He is also the Liberal Democrat Whip for the party's Scottish MPs and was Scottish Education spokesman from 1995 - 97.

Robert's grandfather, also Sir Robert Smith, was Conservative MP for Aberdeenshire and Kincardine, Central Division from 1921 - 45, and his cousin, Alick Buchanan-Smith also served this area as a Conservative MP.