Ole Gunnar Solskjaer says he leaves Manchester United with a "better squad" than he inherited and ready to "kick on" in the challenge for major honours.
He guided the club to second and third-placed Premier League finishes in his tenure but they are currently eighth, 12 points behind leaders Chelsea.
"I look back at every single second here with pride," Solskjaer told MUTV.
"I think everyone knows I've given everything for this club. I wanted us to take the next step to challenge for the league, to win trophies, but unfortunately I couldn't get the results we needed and it's time for me to step aside."
Solskjaer, 48, replaced Jose Mourinho on an interim basis in December 2018.
He was then handed the job full-time in March 2019 on a three-year contract and, in July, signed a new deal with the club until 2024.
Solskjaer was United's fourth permanent manager since Sir Alex Ferguson retired in 2013 - and lasted longer than more experienced predecessors David Moyes, Louis van Gaal and Mourinho.
However, while United finished second last season, they were a distant 12 points behind champions Manchester City and then lost the Europa League final to Villarreal on penalties.
"We were so close in Europe," added a visibly emotional Solskjaer.
"Sometimes that's the fine margin for you, one penalty. We were close and that's something I'll always remember as well. I know the foundation is there, I know they're ready to kick on and I'm sure they will."
While the club's recruitment under the former Molde and Cardiff boss has been more in tune with the expectations of supporters - with Jadon Sancho and Raphael Varane arriving at Old Trafford and Cristiano Ronaldo also returning in the summer - performances have been very poor.
Even prior to the 5-0 thrashing by Liverpool on 24 October and the shambolic 2-0 defeat by Manchester City on 6 November, a number of question marks had already surfaced around the lack of a consistent playing style and tactics.
Despite that, Solskjaer is convinced that the club can bounce back quickly.
"The board and the owners have backed me in bringing good people in, good players in, and I think, or I know, I leave this club with a better squad," he continued.
"Hopefully, the next manager comes in and I want to support him, I want him to be successful. Hopefully I've laid the foundations for that to happen because I know I'm good at what I'm doing."
United travel to Spain to face Villarreal in a crucial Champions League fixture on Tuesday, before league games against Chelsea and Arsenal.
Darren Fletcher is staying on as the club's technical director, while Mike Phelan and Kieran McKenna - who were part of Solskjaer's coaching set-up - will also remain at the club for the time being.
