Martin Narey, chief executive of Barnardo's, is to stand down from the post in January next year in order to spend more time with his family.
Narey, who has been the charity's chief executive for five years, does not have another full-time post lined up. A spokeswoman for the charity said he would look for part-time work or an academic role.
She said Narey's family lived in his home town of Whitby, north Yorkshire, and that he spent four or five days a week staying close to the charity's head office in Barkingside, Essex.
In a statement, Narey said: "My decision to leave in what will be my sixth year has not been taken lightly. But before my departure I am determined to steer Barnardo's through what will be a challenging 2010. I want to ensure our work with children continues to grow in size and effectiveness and that we continue to speak out in defence of the most disadvantaged."
The charity will begin looking for a replacement for Narey immediately.
Narey fronted an emergency appeal for the charity in February because of an expected £3m shortfall in fundraising income this year.
A spokeswoman for Barnardo's said she was unable to say how much the appeal had raised, but that the charity had had a "really positive response".