Professional Footballers' Association chief executive Gordon Taylor will stand down at the end of the season - two years after first announcing his intention to do so.
The 75-year-old has held the role since 1981 and a letter announcing his resignation was sent to members on Wednesday afternoon.
In 2019, the PFA commenced a "full and open review" into its finances.
This review - first announced in November 2018 - was completed in July.
It came following intense criticism of the players' union.
At the time, he said the organisation's entire management committee, including himself, would stand down at the annual general meeting following the report's release.
The 2020 AGM will take place on Thursday, where members will vote on a new governance structure in which the outgoing management committee would be replaced by a players' board and an operational board, which would oversee the day-to-day running of the union.
"As I announced at our previous AGM, now that the independent review process has completed, I too will step down, by the end of the current season," Taylor wrote.
"A new chief executive will be elected following the recruitment procedure recommended by the independent review, and we have already made substantial progress in that direction. I will of course be available in the future whenever needed to support the PFA."
Taylor is credited with negotiating the PFA's biggest source of income - around £25m per year from the Premier League.
But the PFA has recently come under more scrutiny around the issue of dementia, which is a growing concern for former players and the subject of fury from some over a perceived lack of action and support by the PFA.
Earlier on Wednesday, John Stiles - the son of former England international Nobby Stiles, who died in October - had called for the resignation of Taylor and his leadership team.
The PFA announced its Neurodegenerative Disease Working Group (NDWG) last week, which would seek to consult the likes of Dawn Astle - the daughter of Jeff Astle - and former Blackburn Rovers forward Chris Sutton, who has also been critical of the union after his father, a former footballer, was diagnosed with dementia.
Sutton has told BBC Sport he has "no plan to join the taskforce and doesn't want to be associated with the PFA in its current guise".
The PFA also said it would continue to fund Dr Willie Stewart's research into the issue after the neuropathologist found last year that former footballers were between two and five times more likely to die from degenerative brain diseases.
And on Friday it called for heading in training to be reduced in order to protect current players while a potential link between heading and long-term brain injuries exists.
The Taylor timeline
1981 - Takes charge of the PFA and introduces a non-contributory pension scheme for members.
1986 - Helps establish the Football in the Community initiative at six clubs before it is rolled out across all 92 Football League clubs.
1988 - Implements a Youth Training Scheme for 16-to-18-year-old players at professional clubs.
1989 - Agrees to join the Football League as chief executive before reconsidering and staying with the players' union.
1994 - Appointed President of FIFPro (the International Association of Football Players' Unions).
2001 - Secures a £52.2m three-year deal with the Premier League over television revenue after 99% of players back a threat to strike.
2008 - Recognised in the Queen's Birthday Honours and appointed Officer of the Order of the British Empire (OBE).
2015 - Issues a public apology after comparing the Ched Evans rape case with the Hillsborough tragedy.
2017 - Dawn Astle, the daughter of former West Brom and England striker Jeff, walks out of a meeting with Taylor criticising the PFA for a lack of action on dementia research.
2018 - The PFA says it is "disappointing" that a dispute over the eligibility of Ben Purkiss as chairman had become public knowledge.
2018 - An independent review into the PFA is announced.
2019 - Taylor announces he will step down at the conclusion of the review.
2020 - In a letter to PFA members, Taylor says he will step down at the end of the 2020-21 season.
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Regarded as one of football's finest administrators during the 1980s and 1990s, much of the PFA's influence on the modern game can be traced back to Taylor.
His biggest success story at the PFA came in 2001 while negotiating a deal with the Premier League over what the PFA's share of television revenue should be.
England internationals including David Beckham and Gary Neville were among 99% of the PFA's membership to approve strike action until a figure of £52.2m (over three years) was finally agreed, alongside stipulations relating to future deals.
He established community programmes and youth training schemes (now apprenticeships) at all 92 professional football clubs.
He also played a key role in founding the 'Let's Kick Racism Out of Football' initiative in 1993, which later became the organisation Kick It Out.
More recently, Taylor pushed for football to adopt the 'Rooney Rule' to increase the number of Black, Asian and minority ethnic (BAME) coaches in the game.
While the annual PFA Awards evening in April has gone from a men-only sportsman's dinner to an inclusive and glitzy bash, it has not been without controversy.
Football agent Rachel Anderson sued the PFA after being refused admission in 1998 and was awarded damages of £7,500, plus costs.
In 2013, black American comedian Reginald D Hunter used an offensive racist term during his performance at the Grosvenor House hotel in Mayfair, with Taylor saying the performer may have been unaware the language had been an "emotive" subject in football.
There have also been raised eyebrows over perceived lavish expenditure at times, with £1.9m spent on LS Lowry's 'Going to the Match' painting.
In 2013, national newspapers reported Taylor had run up more than £100,000 in gambling debts, and in 2015 he was forced to issue a public apology after comparing the Ched Evans rape case with the Hillsborough tragedy.
Around 300 high-profile former and current players endorsed an open letter calling for Taylor to step down in November 2018 amid a dispute with PFA chairman Purkiss.
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