Fury enjoyed two stints as heavyweight champion and retires with a record of 34 wins, two defeats and one draw.
He announced he was quitting after beating Dillian Whyte in April 2022 but returned to action later that year.
Frank Warren, who promotes Fury, told the BBC he had not spoken to the boxer prior to his retirement announcement.
“I’ve said all along that there is no way I will be trying in any way to influence him,” Warren said.
“If that what he wants to do, that’s great. He’s done everything he can do. Probably been the best British heavyweight of his generation by far.
“Two-time world champion, two closely fought fights against Usyk. He’s got plenty of money, got his wits about him, got a lovely family. God bless him, enjoy.”
All three judges scored last month’s fight in Saudi Arabia 116-112 in Usyk’s favour.
The Ukrainian won their first fight in May 2024 by split decision.
Fury’s retirement appears to mean he will not take on another former world champion, Anthony Joshua, in a long-anticipated all-British showdown.
Joshua said Saturday that a fight with Fury “has to happen this year”.
And Joshua’s promoter, Matchroom’s Eddie Hearn, said he doubted it was the end of the road for Fury.
“If you haven’t got a heart for it anymore and you don’t want to compete anymore, I think retirement is the best option,” Hearn said.
“Disappointing obviously for British fight fans because we’ve got the chance to make the biggest fight in boxing but if that is the last we see of him, he’s had a great career. I doubt it (is the last time we will see him box).”
Fury became world champion for the first time when he shocked Ukraine’s Wladimir Klitschko in November 2015, becoming WBA, IBF and WBO champion.
He was then out of the ring for more than two-and-a-half years, during which he tackled mental health issues.
Fury returned to action in 2018 and became a two-time champion by beating Deontay Wilder to claim the WBC belt in 2020 in the second of a trilogy of fights against the American.
He overcame a big scare against converted MMA fighter Francis Ngannou in 2023, before losing twice to Usyk last year.