The Super Rugby and Super Rugby Aotearoa champions made the announcement to coincide with Havili's 26th birthday.
Havili, 26, considered offers from Japan, but said the priority was to add to the tests he played in 2017, with the new contract taking him through to the next Rugby World Cup in France.
The versatile Tasman Mako back may play for the Crusaders in the midfield next season, with regular centre Braydon Ennor ruled out of Super Rugby Aotearoa with a knee injury.
The Crusaders also have depth in the outside backs with All Blacks Will Jordan, George Bridge and Sevu Reece and impressive Tasman winger Leicester Fainga’anuku.
Havili is the sixth Crusader to sign with the 11-times champions through to 2023, joining Sam Whitelock, Scott Barrett, Jack Goodhue, Cullen Grace and Tom Christie.
Joe Moody, Jordan, Bridge, Richie Mo’unga, Reece and Mitchell Drummond – are contracted through to 2022.
