Timothy Bailey, who taught modern languages at Stowe, the pound;23,000-a-year private school in Buckinghamshire, last week admitted unacceptable professional conduct.
He was described as a Walter Mitty character by the bursar of one school while the head of another said anyone considering employing him would do well to tread carefully.
Dr Bailey hid dismissals from two schools for lying on his CV by changing the dates he worked at Wellington college in Berkshire. Bradley Albuery, the presenting officer, told the disciplinary hearing in Birmingham last week: "In a number of respects, to a number of schools, over a number of years, he has lied."
The GTC heard that between September 1997 and 2004 Dr Bailey lied on applications for jobs at Rossall school in Fleetwood, Lancashire, Stowe, and Newcastle-under-Lyme school. On all three occasions he got the job, but left when the deceit came to light.
He claimed to have a masters degree in philosophy from New York university but had actually only studied there for two weeks before leaving the course.
Rupert Litherland, bursar at Stowe, investigated Dr Bailey after Tracey Hooker, head of languages, raised questions about his conduct.
There were concerns that he had given "unacceptable" help to upper sixth students and failed to mark work. It was also claimed that he had cancelled French lessons prior to a GCSE exam to watch the Cheltenham races.
Mr Litherland said Alan Simpson, bursar of Newcastle-under-Lyme school, had labelled Dr Bailey "a Walter Mitty figure".
He said Richard Rhodes, head of Rossall, had advised him "anyone considering employing Tim Bailey would do well to tread carefully".
Dr Bailey, who was awarded a philosophy doctorate from Lancaster university in 2000, admitted all charges and expressed regret.
"This seems such an unnecessary mess I have created for myself over a number of years," he said. He said that he had been seeing a psychotherapist since last June to deal with the problems which he believes originated in childhood. "I want to learn from this as a teacher and as a person," he said.
Dr Bailey, who studied for his PGCE at York, is currently at Forest school in Wokingham. Forest's head was aware of the disciplinary hearing when the school employed him and provided a positive character statement.