The show was the brainchild of television producer Robert Maxwell and animal trainer Rudd Weatherwax. They created a story about a struggling midwestern farm family and its dog. Weatherwax's dog actor Pal was chosen to play the title character. Pal had played Lassie in the seven MGM movies about the dog character. Pal made the two pilots for the television series, and then retired. The television Lassies that followed were all descendants of Pal, all were male, and all were trained by Weatherwax.
In 1957, oil millionaire Jack Wrather took over the show as producer. He guided it through its greatest years with his wife Bonita Granville Wrather. The first ten years of the series are set on a farm in the American midwest. These years focus on the relationship between Lassie and a young farm boy. The next seven years are about the dog and her Forest Ranger friends. In the last two years, Lassie lives at a home for troubled children. The show was famous for its "Whistle Theme" by Muzzy Marcellino. The Campbell's Soup Company sponsored the show's entire 19-year run. Spin-off merchandise was produced for children such as comic books, play sets, and clothing. The show won two Emmy Awards in its early years.
The show had a large cast over the years. Tommy Rettig played the farm boy for the first three years. Jon Provost became the farm boy in 1957 when Rettig left the show. Jan Clayton played Rettig's mother and June Lockhart played Provost's. Hugh Reilly played Provost's father. Both actresses were nominated for Emmys. The show had its best ratings during the Provost years of the early 1960s. Some episodes from these years were put together to make a color adventure movie for theatres.
Provost left the show in 1964. A new story was developed that took Lassie off the farm. She became the friend of three Forest Rangers. They all had adventures in America's most beautiful natural areas such as Monument Valley and Alaska. In the early 1970s, new rulings about prime time were handed down by the Federal Communications Commission (FCC). These rulings meant that Lassie would be moved to the 8 pm time slot. Lassie had been shown for nineteen years in the 7 pm time slot. Producers felt that this move would not work for the show's child audience. The show was cancelled. Since the cancellation, Lassie has played in reruns and has never been off the air.