Ronald Lindsay, aged 55, who taught physics at Kirkcaldy High, wrote to Mr Dewar raising concerns about qualifications to teach Standard and Higher grade physics.
Fife argued it was entitled to employ someone whose qualification might be in another subject.
The council concluded that Mr Lindsay had not justified his claim and had seriously damaged relations between himself and other staff. It argued he should have raised the matter within the school or with the authority. But Mr Lindsay says he feared his concerns would not be addressed.
He was issued with a final written warning and transferred to Dunfermline High. He unsuccessfully appealed the final warning, and was dismissed last March for gross misconduct after refusing to take up the new post.
Mr Lindsay, who had been with the authority for 12 years, claims he suffered because he had "blown the whistle". He argued his case under the Public Interest Disclosure Act but a Dundee employment tribunal ruled his actions did not amount to a protected disclosure and rejected his complaint.
The tribunal, by a majority, rejected Mr Lindsay's argument that he made the disclosure in good faith. The effect on the teacher complained about, and colleagues, was devastating, the tribunal noted, and such a reaction was entirely predictable. "The applicant was an intelligent man who must have been aware of the effect of writing the letter before he sent it."
The tribunal heard the council operated a special grievance procedure for Mr Lindsay who had raised numerous complaints.