Robert Naylor, former head of St George's Priory pupil-referral unit, in Nottingham, was given a conditional registration order by England's General Teaching Council.
A previous disciplinary hearing in January was told that confidential data on pupils had been discarded in a filing cabinet at a council tip in May, 2003.
The cabinet was sold to a person who discovered the files and telephoned the parents of one of the pupils, who contacted the local authority.
Simon Thomas, Mr Naylor's National Association of Head Teachers representative, told last week's reconvened hearing that the incident was an isolated lapse.
Mr Naylor was also found to have inappropriately used local authority time by attending training courses in December 2002, and in the autumn of 2003, with Jane Deas, his deputy.
The panel found that Mr Naylor failed to maintain accurate records, including registers and financial matters.
Claims that Mr Naylor made excessive telephone calls and sent numerous text messages from August to October 2003, most of them to Ms Deas, from the council's mobile telephone, were not upheld.
Allegations that he unnecessarily appointed a midday supervisor and did not adhere to the code of financial procedures regarding the purchase of equipment, were not upheld.
Mr Naylor resigned from his post at the 37-pupil unit in May 2004.
The 52-year-old had been head of the school since 1996. He now works as a senior teacher in another PRU.
Peter Butler, chair of the GTC panel, said: "This was a serious breach of confidentiality for which Mr Naylor must take responsibility. We have to express surprise at evidence given on behalf of Mr Naylor that this was an inconsequential incident."
The order says that by July 31, 2009, Mr Naylor must be working towards getting a national professional qualification for headship if he wants to be a head again.