[1] Jack Albertson, Patricia Donahue, and Nita Talbot had recurring roles during the show's second season.

Talbot played Beatrice Dane, alias Blondie Collins, a criminal who dragged Nick and Nora into her schemes.

A newspaper columnist wrote that Nora Charles's role was different from that of other female leads in detective programs on television.

Kirk commented:We were the first of the sophisticated detective dramas, and from the scripts it was simple to see that the part of Nora Charles was that of a leading lady who made more than token appearances.

[2]Among the series guest stars was Billy Gray, who appeared at the same time he was cast as James "Bud" Anderson, Jr., in Father Knows Best.