David Hawker, currently education director at Brighton and Hove council, was selected last month by the National Association of Head Teachers'
personnel committee as its next general secretary.
But after it emerged that a large number of NAHT council members had been "underwhelmed" by all three shortlisted candidates, Mick Brookes, a former NAHT president, put himself forward as an alternative.
To challenge Mr Hawker in an election, the Nottinghamshire junior school head needed to secure nominations from three of the NAHT's 11 regional executives by January 21.
This week he told The TES he had already reached that total and was hopeful of securing a fourth today.
The East Midlands executive and two others have agreed to back him, but Mr Brookes declined to name them all until they had written to the NAHT's national president.
Mr Hawker, a 50-year-old former languages teacher who has worked in education for almost 30 years, said he welcomed the opportunity to gain a clear mandate. When an election to succeed David Hart as general secretary in September does take place, he is likely to enjoy the staunch backing of the association's leadership.
Rona Tutt, NAHT president, is already understood to have rung national council members before Christmas to call on them to back the official candidate.
Mr Brookes said: "In my favour is that I am fairly well known as having been national president and I am also a practising primary head. But some people don't want to rock the boat and David Hawker is the executive's preferred candidate.
"Although I am standing within my right under trade union law, I am beginning to feel like a bit of a rebel," he added.
Dr Tutt said once she received the nominations the association would want to hold an election as quickly as possible. Details had not been decided, but she did not anticipate that campaigning would be allowed. Short addresses from the candidates were likely to be included with the ballot paper.
Mr Brookes said he would emphasise the support the association would need to give the thousands of heads unable to implement the final phase of the workforce agreement in September.
Mr Hawker, who has put Brighton at the forefront of the national move to create new children's services departments, said he would stress the key role that the NAHT and heads had in that agenda.
* Age: 50
* Education: Fulbrook county secondary, West Byfleet, Surrey; King Alfred's teacher training college, Winchester; Open University
* Primary teacher since 1969 and head of Sherwood junior, Warsop, Nottinghamshire, since 1985
* Joined the NAHT in 1978. A national council member between 1995-2004 who became national president in 200001