Willie would have to wait until 1917 for his call-up, joining the Royal Signals. By then Charlie was dead, killed in action in 1916. He was just twenty-one and who knows where he might have gone in the game in happier circumstances. Willie, on the other hand, would survive and on demobilisation return to Kilbarchan, impress and in 1921 sign for St. Mirren. He was to stay with the Paisley club for two years, a powerful, right-half, before Sunderland came in, pay a substantial fee and South he went for eight seasons and the best part of three hundred starts. And it would be from Wearside that he would earn two caps, a draw against England in 1924 and a goal versus Wales in 1925.  

Shortly after his thirty-second birthday Willie Clunas would leave Sunderland and head back North once more. He joined Morton in the Scottish First Division but struggling. They improved a little in his first season but were relegated in his second, at which pont he retired from the top-flight but not the game. In fact he took a coaching post in Basel in Switzerland, although without noticeable effect. Both League and Cup results dropped off and he returned home, but not to the Central Belt. He became player-manager of Inverness Thistle, captaining too, with the club winning the Highland League in his second season.

However, in 1937 at the age of thirty-eight Clunas was finally to retire. He left the Highlands, returning to Renfrewshire, becoming match Secretary of Johnstone F.C. and working as an engineer-fitter. He also married, in Johnstone, in 1940, to a local girl, Isabella Love, and they were to have a daughter. And it would also be still staying in Johnstone that he passed away in hospital in Paisley in 1967, to be buried in Woodside Cemetery, Isabella surviving him by eighteen years.