Simon Smith, a teacher at St Peter's RC school, Solihull, also faces union disciplinary proceedings following the revelation that he is number two on the fascist party's West Midlands list in June's European elections.
Mr Smith has been suspended by his school, pending further enquiries. A Solihull education authority spokeswoman said: "The distraction of a media scrum outside the school gates is not helpful when pupils are preparing for exams."
One parent said: "I don't think he should be teaching if he is a member of the BNP but I suppose if he keeps his views to himself at the school he is not doing anything wrong."
Simon Darby, BNP West Midlands regional organiser, said Mr Smith's case was similar to that of Kevin Scott. Mr Scott received an undisclosed settlement from DIY chain Bamp;Q after he was sacked when he stood in local elections in the North-east. "Legally, Simon's employers are on very, very dodgy ground," said Mr Darby.
A spokesman for the Roman Catholic Archdiocese of Birmingham's schools commission said: : "The ethics of a Catholic school are not compatible with the political party to which he is affiliated."
Mr Smith was on a one-year contract that would not have been renewed this summer. He will face disciplinary proceedings from his union, the National Association of Schoolmasters Union of Women Teachers, for bringing the union into disrepute by publishing its name on his biography on the BNP's election website.
Chris Keates, NASUWT deputy general secretary, said the union abhorred the BNP's policies.
Carol Adams, General Teaching Council chief executive, said that membership of the BNP would contravene the council's code of practice, and, if it led to racist practice in schools, it would be a disciplinary offence.
Mr Smith was unavailable for comment, but BNP spokesman Phil Edwards called teaching unions "just bloody Marxists".
This week it also emerged that the BNP's regional organiser in Devon and Cornwall and number one on its list of candidates for the South-west Euro constituency is a school governor.
Tony North said he hoped to use his position as parent governor at Furzeham primary, in Brixham, Devon to argue against multi-culturalism in the school.