Al Hirt, who had a big hit with the song "Java," was grabbed by Billy May to perform the opening and closing title music. Hirt used a technique that musicians know as "triple-tonguing" Which is extremely difficult, especially for the amount of time he used the technique in the theme music.
Kato is a Japanese name, as in the 1936 radio show Kato was Japanese. This was changed in 1939 due to world events. Kato briefly became Korean before settling on Filipino for nearly all of the 1940s. By the 1960s, he was regarded as a generic Asian, enabling Chinese-American Bruce Lee to be cast. Kato is also Chinese in Seth Rogen's The Green Hornet (2011) as a tribute to Lee, but post-1967-pre-2011 adaptations in other media such as comic books, frequently restore the Japanese origin.
The theme song for this show was the same as for the radio version: The Flight of the Bumble Bee by Nikolai Rimsky-Korsakov. It was significantly rearranged for the television series by Billy May who gave it a big band jazz style that was nicknamed Green Bee. The theme is best known for the trumpet solo played by Al Hirt.
In the radio version of the show, the character of Frank Scanlon was the police commissioner. However, since Batman (1966) already had the character of Commissioner Gordon, it was decided to make Scanlon the district attorney to avoid confusion with the other show.
Two Black Beauty cars were built from 440-CID 1966 Chrysler Imperials. After restyling with steel panels and a custom grille, each was painted with black lacquer and fitted with custom wheels. When the series ended, both were sent on tour. After that one was sold to a studio employee and the other was sold to a private collector. There were only two cars built for the series and both are around today. One in the Petersen Museum in LA and the other is in a private collection in South Carolina.