Ozzie and Harriet finally agreed to let them play David and Ricky in the preview show before a studio audience but not the actual broadcast.
The boys did not disappoint their parents.
"They just opened their mouths and you never heard such laughs," said Harriet. "Ricky sounded like a pipsqueak."
David and Ricky joined the cast of "The Adventures of Ozzie and Harriet" in February 1949. Within six months, Radio Life magazine dubbed them "The Crown Princes of Radio."
From the start, Ricky was given most of the funny lines and, as a result, he received most of the attention.
But there wasn't really any rivalry between himself and his younger brother, Nelson said in a 1987 Associated Press interview.
"We were 3 1/2 years apart," David Nelson said. "So when Rick was funny, I laughed with everyone else. And when he became a popular singer, I rooted for him."
David and Rick made their movie debuts in "Here Come the Nelsons," the 1952 comedy released about eight months before the family debuted on television.
During the '50s and early '60s, David Nelson also had roles in the movies "Peyton Place," "The Remarkable Mr. Pennypacker," "The Big Circus," "Day of the Outlaw," "30" and "The Big Show."
For "The Big Circus," he learned to be a catcher in a trapeze act and later appeared professionally as a catcher.
Nelson acted only sporadically after "Ozzie and Harriet" ended; his final acting credit was as the father of Wanda ( Traci Lords) in "Cry-Baby," writer-director John Waters' spoof of the '50s.
Ozzie Nelson died of liver cancer in 1975. Rick Nelson died with six others in a plane crash on New Year's Eve 1985. And in 1994, Harriet Nelson died of congestive heart failure.
Nelson is survived by his wife, Yvonne; sons John, Eric, James and Danny; daughter Teri; and seven grandchildren. Nelson's marriage to Blair ended in divorce in 1975.
Services and burial will be at noon on Thursday at Pierce Brothers Westwood Village Memorial Park and Mortuary.