Two-thirds of headteacher vacancies were difficult to fill, the schools reported, while 12% were never filled at all.
Middle leadership roles were even harder to recruit for, with 59% described as difficult top fill and 20% left unfilled. As many as 27% of Head of School posts failed to recruit.
This is the fifth consecutive year that schools have reported difficulties finding staff across all roles.
Teacher recruitment remains strained, with 37% of school leaders saying they are struggling to find staff due to the mass exodus of workers from the increasingly stressful profession.
Retention is also a growing concern, with 67% of school leaders saying some of their staff have left teaching for reasons other than retirement in the last five years.
Most respondents to the NAHT survey blamed workload pressures and poor work-life balance for the unpopularity of educational posts.
Paul Whiteman, General Secretary of the union, said: “Teaching can be one of the most rewarding careers imaginable, yet workload, high-stakes accountability, insufficient funding, and continuing real-terms cuts to teachers’ and school leaders’ pay drives many committed professionals out of teaching.”
“To create a positive proposition for a career in teaching, the essential components include competitive pay, attractive and flexible working conditions, a healthy work-life balance, opportunities for career-long continuing professional development, and lower risk ways of holding schools to account,” he added.