Court documents show District Judge John E. Neil appointed J. Gregory Coontz on Thursday after reviewing information from former Toyota lawyer Dimitrios Biller, who said the automaker held back safety data.
Crash victim Pennie Green settled for $1.5 million in 2007 but later filed a motion to hold Toyota in contempt.
Biller says he believes he will be called to testify before the special counsel. He says he was subpoenaed and gave documents to the Texas judge in October.
Toyota issued a statement saying the company is confident it acted appropriately in the case.
The appointment was first reported by the Los Angeles Times.