The deputy chairman of JW3, Louise Jacobs, has stepped down after seeing through its merger with the London Jewish Cultural Centre.
Ms Jacobs, who was chief executive of LJCC, said it was "the right time to move on. I feel my job has been done."
The two cultural organisations joined forces in spring after announcing their plans to unite a year ago.
Ms Jacobs said that "the programmes have been well integrated. It's doing well."