Crispin Ellison, described as "one of the fathers of charity legacy management", has died aged 69.
Ellison was one of the founding members of the Institute of Legacy Management and its first director after it was set up in 1999.
He was diagnosed with motor neurone disease in 2015 and it is understood his death on Friday was directly related to the disease.
He was also responsible for developing the prototype for the legacy management software FirstClass by bringing together a group of eight charity legacy officers to collaborate on developing a resource to help the whole sector manage legacy gifts more effectively.
During his time at the ILM, Ellison set up the first training programmes for legacy administrators and helped to establish a professional qualification for charity legacy officers: the Certificate in Charity Legacy Administration.
He took over running the Legacy Link consultancy in 2009, where he worked until his motor neurone disease diagnosis in 2015 forced him to retire.
Ellison was among those who resisted failed attempts in 2014 to dissolve the ILM and reform it as a special interest group of the Institute of Fundraising.
He was presented with a lifetime achievement award and voted lifetime president of the ILM at the 2016 ILM conference.
Matthew Lagden, chief executive of the ILM, who worked with Ellison at the BHF, described him as a fantastic manager with a deep belief in the power of the charity sector to make a difference.
He told Third Sector: "Crispin was a significant and much-loved figure in the world of legacy management and will be greatly missed by many people.
"It is fair to say that without his vision the ILM might not exist, and everyone working in legacy management owes him a huge debt of gratitude.
"It was a privilege to know him."
A joint statement from Lagden and Ashley Rowthorn, director of Legacy Link, said there were few people who had made such an impact on the sector as Ellison.
"For those of us who had the pleasure to work with him during his three decades in legacy management, we will remember his warm smile, his generosity of spirit, his focus and determination, and his passionate commitment to improving the standards and practices in legacy administration," the statement said.
"Today we mourn one of the fathers of charity legacy management, but we are so grateful to have had the opportunity to work with him and learn from him.
"His character as much as his innovations will live on for years to come."
The Crispin Ellison Bursary, which supports students to complete the certificate in charity legacy administration, was established in his name in 2016.
He is survived by his partner Ilana and two step-children.