In January 2015 it was announced that Shinnie had signed a three-year contract with Aberdeen, despite interest from Football League Championship clubs, and would join the club when the summer transfer window opened in June 2015.  He made his competitive debut for Aberdeen on 2 July 2015, against FK Shkëndija in the first qualifying round of the Europa League.  He scored his first goal for Aberdeen on 9 August 2015, in a 2–0 win against Kilmarnock in a Scottish Premiership league game.  Shinnie signed a new contract, due to run until summer 2019, with Aberdeen in January 2017.

Shinnie made his debut for the Scotland national under-21 football team in April 2012.  On 29 September 2015 Shinnie was called up to the senior squad by Gordon Strachan for games against Poland and Gibraltar.  He was called up again in October 2017.