It decided that Jeremy Sui Wah Wong did not intend to defraud Kingswood high school in Bransholme, Hull, when he took compassionate leave to look after his then fiancee who was recovering from a back operation.
Mr Wong, 39, was granted three-and-a-half days leave from work to care for Dawn McGowan, who was due to be discharged from hospital on March 4, 2002.
But he was suspended later that month and sacked in December 2002 after it was discovered that Miss McGowan did not go home until March 8 when Mr Wong had returned to school.
Kevin Beaton, headteacher, said Mr Wong should have told the school the date had been changed, and returned to work.
Mr Wong, who was present at the GTC hearing, denied taking fraudulent leave saying he needed time off to look after Miss McGowan, who needed help with day-to-day tasks.
The ICT teacher, who started at the school in September 2001, said he had to install a bed, shower and toilet downstairs because Miss McGowan could not climb the stairs.
He told the GTC, sitting in Birmingham this week, that he found it hard to cope with what the consultant had told him.
"He spoke of the seriousness of her condition and the level of care she would need, perhaps for the rest of her life, and I was shocked as Dawn had made light of her operation," Mr Wong said.
"I was completely gutted. The last thing on my mind was school. My fiancee had just been dealt a hammer blow and so had our relationship.
"I felt that I had applied (for the leave of absence) in good faith and was trying to cope with everything."
The couple broke up shortly after Miss McGowan's return from hospital.
Valerie Dennis, chair of the GTC panel, said Mr Wong should have told Kingswood school about the change of circumstances but the committee did not deem his actions to be unacceptable professional conduct.
"We accepted that his mind was at the time on other matters," she said.