McCall, who retains his club job, has been appointed assistant national coach.
The former Scotland midfielder, who won 40 caps, will work with Strachan and assistant manager Mark McGhee, who were appointed last week.
McCall has led Motherwell to the Scottish Cup final and Champions League qualifiers in his two years in charge.
The former Bradford boss said in a statement: "I am thrilled to have been asked by Gordon Strachan to join his backroom team.
"Playing for my country was the highlight of my career and I have been fortunate enough to enjoy World Cup and European Championship finals as a player.
"They hold special memories for me and the Scotland supporters deserve a return to those days.
"I am proud to be asked to assist with the national team and look forward to working with an excellent squad of players and two outstanding coaches in Gordon and Mark."