Producers wanted to follow the tradition of marketing this show by selling a license to produce tie-in toys based on it. They offered this license to Hasbro. Hasbro, however, knew that such license deals often ended up with large amounts of unsold inventory, as demand for the toys would die out once the series had started, or especially after it ended. However, they liked the idea of a military-themed toy line, and this inspired them to create G.I. Joe.
Most of the Captains that Lieutenant Rice serves under appear to be veteran Marines with service in both Korea and World War II. In all such cases, this would imply that the Captains were all prior enlisted, most likely having seen significant combat as front-line Marines. This in turn explains the hard and stern nature of many of the officers Lieutenant Rice finds himself working for, in comparison to Rice himself who is a Naval Academy graduate with no overseas combat experience.
This series by Gene Roddenberry would feature many guest stars that would later star in Star Trek Roddenberry's most famous series. They include Leonard Nimoy, Nichelle Nichols, Majel Barrett who were series stars. Other guest stars were Ricardo Montalban (Space Seed), Sherry Jackson (What are Little Girls Made Of), Steve Ihnat (Whom God's Destroy), Barbara Babcock ( A Taste of Armageddon), ans Kathryn Hays (The Empath) as well as Gary Lockwood (Where no Man has Gone Before)
The series was produced during the very early stages of the Vietnam War, before the United States viewed its involvement as a prolonged conflict. As a result, there are references in the series to Marines deploying for "counter insurgency operations in Southeast Asia" while the term "Vietnam War" is never used and the country of Vietnam is rarely referred to directly. Ironically, had the series continued into the mid 1960s, this would have been during a period when the Marine Corps would deploy thousands of troops in what by then had become a full-scale conflict.
Similar-looking character actors John Doucette and John Milford appear in the first episode as a sergeant and corporal. In later episodes Milford's character continues, upgraded as a sergeant.