In the program's later years, Steven Douglas married Barbara Harper (Beverly Garland) and adopted her young daughter Dorothy Anne ("Dodie") (Dawn Lyn).

The first season, consisting of 36 episodes, was directed in its entirety by Peter Tewksbury, the Emmy-winning director of Father Knows Best, who produced and occasionally scripted the programs.

[3] During the 1964 fall season, William Frawley, who played Bub, was declared too ill to work by Desilu Studios, as the company was informed that insuring the actor would be too costly.

He was replaced by William Demarest, who played his hard-nosed brother (great) Uncle Charley, introduced partway through the 1964–1965 season (the last on ABC).

[5] My Three Sons moved to the CBS television network for the 1965–1966 season after ABC declined to underwrite the expense of producing the program in color.

Along with the change in networks and the transition to color, Tim Considine (who had earlier worked with Fred MacMurray on The Shaggy Dog), playing eldest son Mike, had chosen not to renew his contract due to a clash with executive producer Don Fedderson over Considine's wish to direct but not co-star in the series.

In an August 1989 interview on the Pat Sajak Show, he explained that he was also devoted to car racing, which his contract forbade.

His character was written out, along with Meredith MacRae, who had played his fiancée Sally, in a wedding episode that was the premiere of the 1965–1966 season on CBS.

To keep the show's title plausible, the show's head writer, George Tibbles, fashioned a three-part story arc in which an orphaned friend of youngest brother Richard (Chip, played by Stanley Livingston), Ernie Thompson (played by his real-life brother, Barry Livingston), awaits adoption when his current foster parents are transferred to the Orient.

The family soon appears before a judge who researches the law and determines that its intent is to ensure that a full-time caregiver is in the household.

As Charley meets that role and has had a change of heart about Ernie, he assents to a legal fiction that declares him the Douglas family's "housemother".

In the season premiere episode, "Moving Day", the Douglas family and Uncle Charley relocate from the fictional Midwestern town of Bryant Park to Los Angeles, California.

The following season, the newlyweds discover that Katie is pregnant and she gives birth to triplets named Robert, Steven, and Charles.

His new bride, widowed teacher Barbara Harper (Beverly Garland), brings with her a five-year-old daughter, Dorothy "Dodie" (Dawn Lyn), whom Steve adopts.

A 1971 television pilot with Don Grady and Tina Cole called Three of a Kind, then retitled Robbie—about Robbie, Katie, and the triplets moving to San Francisco—was filmed but not picked up as a series.

Richard X. Slattery and Pat Carroll guest-starred as the landlords of the apartment block into which Robbie and Katie move.

However, Don Grady had informed the producers of his intention to leave the series and pursue a new full-time career as a composer, which he ultimately did.

This storyline continues a plot idea that originally began in the fourth season, when the Douglases visited Scotland on the pretense of having been told they had inherited a castle in the Highlands.

The reasons behind this move concerned the sale of actress-comedienne Lucille Ball's studios to the Gulf + Western conglomerate, which owned Paramount Pictures.

Don Fedderson Productions, which produced My Three Sons (along with Family Affair starring Brian Keith), had to quickly make other arrangements for filming.

From 2012 to 2014, and also from October 2015 to February 2016, MeTV aired the Season 6-10 episodes in heavy rotation, and most closing credits included the original sponsor tags, such as those for Kellogg's.

MacMurray and most of the cast took part in Thanksgiving Reunion with The Partridge Family and My Three Sons, which aired on ABC on November 25, 1977.

The special was notable for featuring footage from early black and white episodes of My Three Sons that, at this point in time, were not in syndication.