Christopher Bradbury, 54, was headteacher at St Mary of the Angels Roman Catholic primary, in Walsall, West Midlands, for 10 years until he resigned in June 2002.
During a competence hearing this week the GTCE heard that Mr Bradbury consistently failed to reach goals set to improve the school.
Francis Patton, chairman of governors, believed the school had serious weaknesses. He said: "Parents were complaining about the staffing levels, and the school's test results and position in the league tables were disappointing.
"I told Mr Bradbury about my concerns and about the lack of an improvement plan. The school was run in a very casual manner."
He said inspectors from Walsall council were called in and a mentor was provided to assist Mr Bradbury, who was given a written warning.
But by November 2001, the targets were still not met and a second hearing was arranged for March 2002.
Mr Patton said: "We came to the conclusion that Mr Bradbury had not made sufficient progress.
"A final written warning was given and three months in which improvements had to be shown."
But Mr Bradbury and his union representative formally handed in his conditional resignation before a third meeting due to be held in June 2002.
Mike Onion, a school improvement consultant for Walsall council, said that Mr Bradbury's biggest failing was that he did not understand what was expected of him.
He said: "Christopher did not have full understanding. He failed to look at what he was supposed to achieve. "His main difficulty was that documents were the end of a process rather than part of a process or the beginning of it."
The hearing will be reconvened at a later date.