Stuart finally joined the club on a permanent basis after enjoying two loan spells at Rugby Park.
The 21-year-old started his career at Celtic, where he also spent loan spells at Greenock Morton and Dumbarton. After the conclusion of the 2015/16 season, Findlay joined Newcastle United, following his release from Celtic. The six-foot-three defender made his first team debut for The Magpies in January 2017, in a FA Cup tie against Birmingham City.
Stuart has also represented Scotland from U16 to U21 level.
He scored his first senior goal in Killie's 2-1 win over St Johnstone in December 2017.