For this series, Efrem Zimbalist, Jr. was provided with an F.B.I. identification card that had a recent photograph of him, fingerprints from his Army service, and an identification number that was only one digit less than a genuine number.
Of the series that Quinn Martin produced, this series was his longest running of all. It aired nine seasons.
In June of 2009, real-life F.B.I. Director Robert Mueller honored Efrem Zimbalist, Jr. with a plaque and badge, making Zimbalist an honorary F.B.I. Agent for his work on the series.
Originally sponsored by the Ford Motor Company, which supplied all of the vehicles used on the show.
F.B.I. memos, which were recently released under the Freedom of Information Act, have revealed that the real F.B.I. had a veto over casting for guest stars on the series. According to the memos, Robert Blake and Bette Davis were barred from making guest appearances on the series.