Sir Stuart Etherington, the chief executive of the National Council for Voluntary Organisations, is due to step down from his position after more than 25 years in the role.
Etherington is set to retire from his post later this year and an open application process will be launching today.
The umbrella body's membership has grown from 400 to 14,000 since he took up his post in 1994 and in 2010, Etherington was knighted for his services to the voluntary sector.
"It has been a huge privilege to work alongside the incredible people and organisations that make up our sector," he said.
"I would strongly encourage anyone to consider applying for this job. The pace of change in the sector has been phenomenal over the last twenty-five years, and this is a trend I am sure will continue, making this an immensely exciting and rewarding role.
"You will have the privilege of leading a high-performing organisation full of talented staff providing practical support to thousands of members every year, while also playing a crucial role in shaping a wider policy environment that enables charities and volunteering to thrive."
NCVO chair, Peter Kellner added: "Stuart has made a truly invaluable contribution to NCVO and the sector over his time as chief executive. He has guided NCVO from strength to strength during even the most challenging times. It has been a pleasure to work alongside him for the last two years.
"One of Stuart's great skills has been in adapting NCVO to meet new challenges. As the sector itself continues to change, we are seeking someone who can continue to bring fresh ideas alongside sharp strategic thinking.
"The interview panel will also be looking for someone with an unimpeachable track record of standing up for integrity and transparency, and a clear commitment to valuing and nurturing difference and diversity."
The deadline for applications is Friday 15 March 2019 and an appointment is expected to be made in the summer.
The interview panel is set to consist of: Peter Kellner, chair of NCVO, Paul Breckell, treasurer of NCVO, Tiger de Souza, trustee of NCVO, Julia Cleverdon, chair of the NCVO human resources and renumeration committee, and Julia Unwin, chair of the Independent Inquiry into the Future of Civil Society. Their recommendation will then be subject to final approval by NCVO's trustee board.