After the cancellation of Robert Keeshan's Saturday television show "Mister Mayor", the secondary characters joined this show. These individuals included Dudley D. Dudley, whose job was being a substitute statue, Rollo the Hippopotamus, and Aunt Maude.
With the addition of Mr. Baxter in 1968, this show because one of the first (if not the first) racially integrated Children's shows. The character was not intended to be an American of African descent. James E. Wall, who worked as the show's Stage Manager expressed interest in playing the part, and made the case for such inclusion on the show. Producers agreed to cast him in the part after Wall agreed to go through auditioning.
One of the show's long-running gags was the "Ping-Pong Ball Drop", instigated by the telling of a joke (usually a knock-knock joke) by Mr. Moose, in which the punchline included the words "ping-pong balls". At the mention of those three words, a shower of ping-pong balls was released from above on the Captain.
Several cartoon shorts were featured over the course of the series' run, including: A cartoon starring a funnel-capped shape-shifting boy named Tom Terrific was part of the show in the 1950s and 1960s. Tom had a sidekick named Mighty Manfred the Wonder Dog, and a nemesis, Crabby Appleton ("Rotten to the core!"). Other cartoons included Lariat Sam, which was developed by veteran game show announcer Gene Wood, then a show staffer (who also sang the cartoon's theme song). The British cartoon Simon in the Land of Chalk Drawings appeared in the 1970s, featuring a child with magic chalk who could create all sorts of short-lived creations in short adventures. (The original version featured a British narrator, Bernard Cribbins, but Keeshan's voice was dubbed onto the cartoons for their U.S. airing). Another British-produced cartoon, Ludwig, about a magical egg-shaped robot, was also included around the same time as Simon. The cartoon's musical score consisted of selections from the works of Beethoven. Also appearing in the 1970s was The Most Important Person, a series of five-minute segments on the importance of life, and The Kingdom of Could Be You, a series of five-minute segments on the importance of careers and the work world. The cartoon series called The Toothbrush Family was based on an extended family of hygiene utensils, as the name suggests; they would embark on adventures based in the bathroom, like water skiing in the tub, or rescuing friends caught in the drain. Episodes were generally a few minutes each and basically revolved around teaching children the importance of dental care. A silent cartoon in the 1970s named Crystal Tipps featured the adventures of a young girl. Later reruns were narrated by the voice of Mr. Moose. Another British favorite, The Wombles, was also featured. The Red & Blue shorts from Italy were also shown. The Undersea Adventures of Captain Nemo, featuring a family of sea explorers, was featured, as well.
At the end of each episode, the Captain always encouraged parents watching the show to spend some quality time with their children every day, and he often demonstrated various creative ways in which to do so. Later that changed to him saying, "Well, what would you like to do today? You know it could be a good day for..." then a song would sing many different things while short film clips of each thing are presented, then the song ended with the singers saying, "There's so much to do. These things are just a few." Then it would cut back to the captain who would end with, "So whatever you do, have a great day."
At the beginning of the show, the Captain would say hello, then hang up his keys. Once he did this, the opening music stopped playing. when he picked them up again, the music would start playing again.
Other regular features included The Magic Drawing Board and the Captain's "Reading Stories" sessions, which introduced kids to stories such as Curious George, Make Way for Ducklings, Stone Soup, Caps for Sale, and Mike Mulligan and His Steam Shovel. The Sweet Pickles books were also featured.
Keeshan also had a recurring role as the Town Clown, a pantomime piece that took place in and around the exposed wagon home of a tramp-like circus clown. Like the character Clarabelle that he played on Howdy Doody, the Town Clown never spoke.
In 1986, the American Program Service (now American Public Television, Boston) integrated some newly produced segments into reruns of past episodes, distributing the newer version of the series on PBS until 1993.
Captain Kangaroo had a loose structure, built around life in the "Treasure House" (later known as "The Captain's Place") where the Captain (the name "kangaroo" came from the big pockets in his coat) would tell stories, meet guests, and indulge in silly stunts with regular characters, both humans and puppets.
In September 1981, CBS shortened the hour-long show to a half-hour, briefly retitled it Wake Up with the Captain, and moved it to an earlier time slot; it was moved to weekends in September 1982, and returned to an hour-long format. Captain Kangaroo was cancelled by CBS at the end of 1984.
One never knew exactly what would happen from one episode to the next, although at certain times of the year, such as the Christmas season, paper cutout versions of such stories as The Littlest Snowman would be shown.
Beginning in 1974 and continuing throughout the rest of the 1970s and into the 1980s, the show opened with different people wishing the Captain "good morning". Many of the openings featured noncelebrities, but some featured stars from TV shows, most of which broadcast over CBS, such as The Bob Newhart Show, The Price is Right, Match Game, M*A*S*H, Alice, and One Day at a Time, as well as characters with a connection to another network; including William Shatner and Leonard Nimoy, dressed as Captain Kirk and Mr. Spock, characters from the Peanuts cartoons, Big Bird from Sesame Street, and Fred Rogers from Mister Rogers' Neighborhood. The montage of "good mornings" always ended with the Captain himself returning the greeting before the opening credits ran.
Favorite characters on the show were Grandfather Clock (voiced by Cosmo Allegretti), Rollo the Hippo, and Dancing Bear. Dancing Bear was mute and only appeared in short subject features. He often danced waltzes to background music.
Familiar props included a mockup of a talking cathedral-style radio that Keeshan simply called Radio. Keeshan would turn the large knobs on Radio to get a conversation going. Reminiscent of the old Atwater Kent cathedrals, Radio had a rather interesting conversation with a smaller transistor radio in one show. Also featured was a huge Colgate toothpaste box with a large windup or clockwork key on the side. Keeshan turned the key to play a jingle ("Colgate Fluoride M-F-P/Helps Prevent the Cavity/And it Tastes Great, Naturally!") for the show's sponsor, Colgate Toothpaste.
Despite the show's iconic nature, and enduring popularity, the series has never been officially released to home video/DVD or any streaming service. Very little film footage of the series remains, and what does exist was owned by Bob Keshan, and subsequently his estate, who have maintained a tight grip on their film holdings.