Nelson was born March 20, 1906 in Jersey City, New Jersey. He was the second son of Ethel Irene (née Orr) and George Waldemar Nelson. His paternal grandparents were Swedish and his mother was of English descent. Nelson was raised in Ridgefield Park where he was active in Scouting, earning the rank of Eagle Scout at age 13. He played football at Ridgefield Park High School as well as during his college years at Rutgers University. He was a member of the Cap and Skull fraternity. He graduated from Rutgers University with a bachelor’s degree and earned a law degree from Rutgers School of Law, Newark, New Jersey, in 1930. Nelson was made a doctor of humane letters by Rutgers University in 1957. As a student he made pocket money playing saxophone in a band and coaching football. Nelson was rejected to be the vocalist for the Rutgers Jazz Bandits, led by Scrappy Lambert and later Hawley Ades. Nelson was not discouraged and was gracious about this rejection when he met Ades years later. During the Depression, he turned to music as a full-time career.

Nelson started his entertainment career as a band leader. He formed and led “The Ozzie Nelson Band,” and had some initial limited success. Nelson made his own “big break” in 1930, when The New York Daily Mirror ran a poll of its readers to determine their favorite band. Since he knew that news vendors got credit from the newspaper for unsold copies by returning the front page and discarding the rest of the issue, he cannily had his band’s members gather hundreds of discarded newspapers and fill out ballots in their own favor. They edged out Paul Whiteman and were pronounced the winners.

From 1930 through the 1940s, Nelson’s band recorded prolifically—first on Brunswick (1930–1933), then Vocalion (1933–1934), then back to Brunswick (1934–1936), Bluebird (1937–1941), Victor (1941), and finally back to Bluebird (1941 through the 1940s). Nelson’s records were consistently popular, and in 1934, Nelson enjoyed success with his hit song, “Over Somebody Else’s Shoulder,” which he introduced. Nelson was their primary vocalist and, from August 1932, he featured in duets with his other star vocalist, Rose Anne Stevens, who appeared in the 1942 movie, Down Rio Grande Way. Later in his big band career, Harriet Hilliard replaced Stevens, Nelson’s calm, easy vocal style was popular on records and radio and quite similar to son Rick’s voice, Eric Hilliard (“Ricky”) and Harriet’s perky vocals added to the band’s popularity.

In 1935, “Ozzie Nelson and His Orchestra,” as they were being called, had a number one hit with “And Then Some”, which was number one for one week on the U.S. pop singles chart. Nelson wrote and composed several songs, including “Wave the Stick Blues”, “Subway”, “Jersey Jive”, “Swingin’ on the Golden Gate”, and “Central Avenue Shuffle”.

In October 1935 he married the band’s vocalist Harriet Hilliard. The couple had two children: the older, David (1936–2011), became an actor and director, and the younger, Eric Hilliard (“Ricky”) (1940–1985), became an actor and singer.

He married band singer Harriet Hilliard in 1935. They had two sons, David (born in 1936) and Eric (known as Ricky, born in 1940). The couple remained married until Ozzie’s death in 1975. His grandchildren include actress Tracy Nelson and musicians Matthew Nelson and Gunnar Nelson. He was also the former father-in-law of Kristin Harmon and June Blair.

Ozzie Nelson appeared with his band in feature films and short subjects of the 1940s, and often played speaking parts, displaying a tongue-in-cheek sense of humor, as in the 1942 musical Strictly in the Groove. He shrewdly promoted the band by agreeing to appear in “soundies,” three-minute musical movies shown in “film jukeboxes” of the 1940s. In 1952, when he and his family were established as radio and TV favorites, they starred in a feature film, Here Come the Nelsons, which actually doubled as a “pilot” for the TV series.

In the 1940s, Nelson began to look for a way to spend more time with his family, especially his growing sons. Besides band appearances, he and Harriet had been regulars on The Raleigh Cigarette Program, Red Skelton’s radio show. Nelson developed and produced his own radio series, The Adventures of Ozzie and Harriet. The show originally aired in 1944, with their sons played by actors until 1949. In 1952 it moved to television, where David and Ricky appeared on-camera. The radio version continued for another two years, and the last television episode aired in 1966.

In 1973, Ozzie Nelson published his autobiography, Ozzie, (Prentice Hall, 1973, ISBN 0-13-647768-2).

Nelson suffered from recurring malignant tumors in his later years, and eventually succumbed to liver cancer. He died at his home in the San Fernando Valley at 4:30 a.m. on June 3, 1975, with his wife and sons at his bedside.

Cultural historians have noted that the on-screen laid-back character was very different from the real-life Ozzie Nelson, who has been characterized as an authoritarian figure who monitored every aspect of his children’s lives. In 1998, A&E broadcast a documentary entitled Ozzie and Harriet: The Adventures of America’s Favorite Family, which depicted Ozzie Nelson as a dictatorial personality who “thwarted his sons, preventing them from attending college and reminding them that they were obliged to work on television”. Author David Halberstam has written, “the Nelsons arguably were a dysfunctional family. In real life, Ozzie was a workaholic who stole his sons’ childhood (by having them grow up in show business)”.

When his elder son David died in 2011, he was cremated, having chosen a niche in Westwood Memorial Park’s outdoor Garden of Serenity columbarium rather than interment in the Nelson family plot.