Defoe, 33, moved to Wearside from MLS outfit Toronto back in January 2015, penning a 3½-year deal worth £80,000 a week — with American Altidore heading the other way.
Allardyce said: “Having just been reminded that he was swapped for Altidore, it's one of the best bits of business the club has done for a long time.
“Due respect for Mr Altidore, he scored one goal in two years, so that was a good deal, wasn't it?
“The good thing for Sunderland was that Jermain couldn't wait to get back to England.
“We were the team that brought him back to play in the Premier League and it has paid off handsomely for him and for us."