Tuitupou, who has made 16 European appearances was the ideal candidate for the role according to Sale's executive director of sport Steve Diamond.
"Sam joined us in the Summer and has been outstanding at training, leading by example and motivating others," he said.
"He has captaincy experience from his Auckland days. It was a difficult decision - there were three or four lads who 'stuck their hands in the air' and wanted to be captain - but we thought that Sam would be here with us and not be playing in internationals. That was one of the considerations with the new team and the new environment at the club: it's the right way.
"We're not having vice captains. If Sam is unavailable, we'll pick a captain as we go forward. We've got two other leaders in the group - Joe Ward and Nick Macleod - who are our 'governors'. They look after discipline for us and that's how it works out for the team."
Sale kick off their Amlin Challenge Cup campaign with a trip to Brive in November before welcoming Rugby Club La Vila to Stockport the following week.