Smith – who won 21 trophies in two spells as Rangers manager – was well respected across the Old Firm divide and led Scotland between 2004 and 2007, with current Motherwell manager Graham Alexander a part of the national squad which Smith led to Kirin Cup victory in Japan in 2006 and a famous 1-0 home Euro 2008 qualifying win over France in October 2006.
Alexander said: “It’s terrible news. Everyone knew he’d been ill this year.
"I didn’t realise to what extent. There are just fantastic memories of the man for me.
"He sent me a great message when I came to work at Motherwell. Fantastic man to think of me at that time.
"I owe the resurgence of my Scotland career to him.
"He called me up after a while out of the squad. And I had without doubt my best spell as a Scotland player playing for Walter.
"Brilliant man first and foremost from my experience of him, how he was on a human side of it, how he treated everybody.
"To play under him was an absolute privilege.
"Actually being picked by Walter I thought I had won already because it was an achievement just to be picked by him.
"He was just a genius of a man.”
Smith, whose senior playing career saw him turn out for Dundee United and Dumbarton, also managed Scotland under-18s, Scotland under-21s and Everton.