Glasgow born outside left William Lennie played junior football for Mossvale and Maryhill before joining Queen’s Park in December 1901. He made his Scottish League debut at the end of December against St Mirren, scoring once in 9 appearances before joining Glasgow Rangers in May 1902. At Rangers he scored twice in 10 appearances before joining Dundee in July 1903. After a brief spell with Royal Albert in 1904 he moved south to join Southern League Fulham in September 1904, making his Southern League debut against Southampton the following month and scoring twice in 26 appearances including 8 games in their FA Cup run that saw them beaten by eventual winners Aston Villa in the quarter final, but after a single season with The Cottagers he returned to Scotland to join Aberdeen in June 1905.
It was at Aberdeen that his career took off and he won his first cap for Scotland, in so doing becoming Aberdeen’s first player to be capped, when he played against Wales at Dens Park, Dundee, scoring in a 2-1 victory, in March 1908. He then won a second cap in a 5-0 victory over Ireland at Dalymount Park, Dublin a week later. He also played for The Scottish League in a 3-1 victory over The Irish League in Belfast in October 1910.
One of the first players to receive a benefit match from Aberdeen, he scored 66 goals in 252 appearances for Aberdeen before joining Falkirk for £30 in November 1913. He moved to St Johnstone in October 1914, being released at the end of the 1914-15 season, and later played for J.M. Henderson’s before retirement.