Jack Sullivan has stepped down as managing director of Women’s Super League (WSL) side West Ham.
The 21-year-old, who was 18 when he took the job in May 2017, is the son of Hammers joint-chairman David Sullivan.
During his time in the role, West Ham secured a licence to play in the WSL from 2018 and reached the Women’s FA Cup final the following year.
Sullivan also starred in the BBC Three television series Britain’s Youngest Football Boss.
“This has been a very tough decision but, after much consideration, I believe it is the right time to move on,” Sullivan told the club website.
“My time working with the women’s team has been a fantastic and hugely rewarding experience.
“When I look back on where we were four years ago, I am extremely proud of team and the progress and improvements that we have all made since then.
“I feel we have put foundations in place that will give the women’s team a great chance of going on to bigger and better things in the future.”
General manager Aidan Boxall, who joined the Hammers in April 2020, will take on greater responsibility for the day-to-day running of the club.
West Ham finished ninth in the Women’s Super League this season.
Earlier this week, former England full-back Paul Konchesky was appointed as assistant manager of the side, which has been under the leadership of New Zealander Olli Harder since late last year.
“When I came to the club in December, it was immediately clear to me how much hard work he (Sullivan) has put in to build the foundations of what is in place here – and that was a key factor in my decision to join West Ham United,” Harder said.
“He has created a fantastic work ethic and family feeling around the women’s team, and he leaves with a lasting legacy of having established West Ham United in the FA WSL and given us a great opportunity of going on to even greater success in the future.”