Captain Pontus Jansson will leave Brentford when his contract ends this summer to rejoin Swedish club Malmo.
The defender, 32, began his career at Malmo before spells at Italian club Torino and Leeds United.
Jansson joined Brentford in 2019, helping the Bees earn promotion to the Premier League in 2021 after a 74-year absence from England’s top flight.
“I am so thankful for my time here and the journey that the club and I have been on,” he said.
Jansson, who came through the youth system at hometown club Malmo before leaving for Torino in 2014, has scored four times in 115 games for Brentford.
“It is tough to put these last four years into words,” added the Sweden international centre-back.
“When I joined, we were a middle-of-the-Championship club and now I’m leaving a club that’s hopefully about to finish top 10 in the Premier League.
“I’ve been on a massive personal journey as well. I matured into a captain, and a leader, because of this club.”
Jansson joined Leeds in 2016, initially on loan, making 120 appearances for the club before then-Championship rivals Brentford signed him for an undisclosed fee.
He was immediately installed as captain and helped the Bees win promotion before signing a new deal in January 2022 until this summer.
Jansson made 37 league starts as Brentford secured their Premier League status for another season, but a hamstring injury has limited him to nine starts this term.
After being forced off against Newcastle last Saturday, he said it was his “final game in red and white”.
“I have so much pride looking back on my time here,” added Jansson.
“The Brentford fans took me into their hearts from day one and the love has only grown between us. I wanted to play every game between now and the end of the season to finish on a high, but injury means that is not possible.”
Manager Thomas Frank said: “He came in and was a big part of the reason why we could, straight away, compete for Premier League promotion.
“I know it was a big dream for Pontus to play in the Premier League and he probably played his best season that first year in the Premier League.
“Pontus is one of the players I created a strong bond with. He’s given so much to the club and the team. I wish him and his family all the best for the future.”