A product of Edinburgh Academy, Kinghorn, joined the club on return from the 2015 World Rugby U20 Championship in Italy.
Kinghorn first signed professional terms off the back of Scotland U20’s World Championship in 2015 and made his club debut later that season. He enjoyed a breakout campaign under Head Coach Richard Cockerill in 2017/18 and finished the PRO14 campaign with the most metres gained in the league and a place in the end of season Dream Team.
He was then rewarded with his senior international debut in Scotland’s 2018 Calcutta Cup win over England at Murrayfield and scored Scotland's first Six Nations hat-trick since 1989 in the 33-20 victory over Italy a year later.
In February 2018, Kinghorn signed a new deal with Edinburgh Rugby, committing his long-term future to the club.
He was selected in the 31-man squad for the 2019 Rugby World Cup. 2020 saw him cement his name in Scotland's squad for the 2020 Six Nations.
In May 2021 he become Edinburgh's 35th centurion and beat Sam Hidalgo-Clyne to the youngest club centurion when he hit the number at the age of 24 years and 117 days
|2015 - present|
|2018 - present|
|2015 - 2016|
|2017 - 2018|