It has been a disappointing season for a club who finished ninth on their Premier League return last year.
Injuries to key men hit a small squad hard, as Leeds shipped plenty of goals and spent the season battling at the wrong end of the table. The axe fell on Marcelo Bielsa in February with Jesse Marsch replacing the Argentine.
The club's board have received plenty of criticism for their role in United's struggles, with negative chants aimed at the Leeds hierarchy in the final home game of the season against Brighton.
Owner Radrizzani described this season as a "battle" for everyone involved with the club but has promised improvements heading into the 2022-23 campaign.
"We are naturally delighted to see the 2021/22 season come to a conclusion with Leeds United remaining in the Premier League," he said in a statement.
"This has been a painful season for everyone, from the board to the fans in the stands, the changing room to the ticket office, it has been a battle.
"The campaign has been blighted by serious injuries to key players and having to make an unplanned managerial change was an incredibly tough decision.
"Staying in the Premier League was our objective this year and we’ve managed to obtain our top-flight status, but this is not success and improvements are needed.
"As a board we will work hard with Jesse Marsch this summer to improve the squad and find a way to deliver the kind of performances you all deserve.
"We believe that with time and a full pre-season, Jesse will be the man to take this club forward.
"Your support for the team at Elland Road and at the 19 top-flight away grounds you have visited has been unrivalled and we can’t thank you enough.
"The hard work for the 2022/23 season is already underway."