Emslie was educated at the Edinburgh Academy and Trinity College, Glenalmond, before studying at Gonville and Caius College, Cambridge (BA) and the School of Law of the University of Edinburgh (LLB).
[1][2] As a young man he was a keen sportsman, playing scrum-half for Edinburgh Wanderers and midfield for Spartans F.C.
During a game between Oxford and Cambridge University football clubs at Wembley Stadium, Emslie's was the first name ever displayed on the new electronic scoreboard.
[3] He served from 1979 to 1987 as Standing Junior Counsel (legal advisor appointed by the Lord Advocate) to the Department of Health and Social Security, and from 1985 to 1988 as an Advocate Depute, representing the Crown in prosecutions and appeals in the High Court.
He was promoted to the Inner House of the Court of Session in 2005, at which time he was appointed to the Privy Council.