Had an IQ of 159.
Had to drop out of the University of California-Los Angeles because he tore his shoulder ligaments, which would prevent him from throwing the javelin again, and he was attending UCLA on an athletic scholarship.
He encouraged his children, not to make the same mistake Landon had made, when he was a teenager. As a result, his children were told to study, without watching television, except if it was "Little House on the Prairie" (1974).
He once invited Shirley Jones to an art exhibit.
He smoked 4 packs of unfiltered Menthol cigarettes a day during his lifetime, which probably contributed to the pancreatic cancer that killed him.
He was left-handed, and his awkward handwriting (he often hand-wrote scripts) sometimes made it difficult for his secretary to read what he'd written).
His adoptive son, Mark Landon, died in May 2009 at the age of 60.
His birthplace, Forest Hills, is a neighborhood area in Queens, New York.
His daughter Leslie Landon attended the same middle school as his future "Little House on the Prairie" (1974), co-star, Melissa Gilbert. Leslie heard Gilbert in the school cafeteria say that she was going to play Laura Ingalls.
His father died of a heart attack in February 1959.
His last wife was former make-up artist Cindy Clerico, whom he met near the end of the "Little House" run in 1981, and married two years later.
His mother Peggy died on March 15, 1981.
His parents were Jewish and Irish Catholic.
His second wife, Marjorie Lynn Noe, was one of the few people who refused to attend his funeral, because she told her children that the divorce had already been like a death to her.
His show "Highway to Heaven" (1984) was canceled due to his co-star's, Victor French's death at the end of the fifth season.
His stepdaughter, Cheryl, recalled in his biography "I Promised My Dad" that once Landon was diagnosed with pancreatic cancer, he realized that all the years of smoking, drinking and eating an unhealthy diet had taken their toll. Later, despite going on a regimen that included a naturalistic approach to the cancer (coffee enemas and a healthy diet), Landon was devastated to learn that the cancer had tripled in size.
In 1954, he was the national high school record holder in the javelin throw.
Inducted (as a cast member of "Little House on the Prairie") into the Hall of Great Western Performers of the National Cowboy and Western Heritage Museum in 1998.
Interred at Hillside Memorial Park, Culver City, California, USA.
Is buried at the same cemetery as his TV father, Lorne Greene (Hillside Memorial Park, Culver City, California).