Dangerfield was born in Babylon, in Suffolk County, Long Island, New York. He was the son of Jewish parents, Dorothy "Dotty" (Teitelbaum) and the vaudevillian performer Phil Roy (Phillip Cohen). His mother was born in Hungary. Dangerfield's father was rarely home; Rodney would normally see him only twice a year. Late in life, Rodney's father begged him for forgiveness, and Rodney obliged.
After his father abandoned the family, his mother moved him and his sister to Kew Gardens, Queens, and he attended Richmond Hill High School, where he graduated in 1939. To support himself and his family, he sold newspapers and ice cream at the beach, and delivered groceries.
At the age of 15, he began to write for stand-up comedians, and he himself began to perform at a resort in Ellenville, New York, at the age of 19 under the name Jack Roy, to which he legally changed his name. He struggled financially for nine years, at one point performing as a singing waiter until he was fired, and also working as a performing acrobatic diver before giving up show business to take a job selling aluminum siding to support his wife and family. He later said that he was so little known then that "at the time I quit, I was the only one who knew I quit!"
In the early 1960s he started down what would be a long road toward rehabilitating his career as an entertainer, still working as a salesman by day. He divorced his first wife Joyce in 1961, and returned to the stage, performing at many hotels in the Catskill Mountains, but still with minimal success. He fell into debt (about $20,000 by his own estimate), and couldn't get booked. As he would later joke, "I played one club—it was so far out, my act was reviewed in Field & Stream."
He came to realize that what he lacked was an "image"—a well-defined on-stage persona that audiences could relate to, and that would distinguish him from similar comics. Returning to the East Coast, after being shunned by the premier comedy venues, he began to develop a character for whom nothing goes right.
He took the name Rodney Dangerfield, which had been used as the comical name of a faux cowboy star by Jack Benny on his radio program at least as early as the December 21, 1941, broadcast, and later as a pseudonym by Ricky Nelson on the TV program The Adventures of Ozzie and Harriet. The Benny character, who also received little or no respect from the outside world, served as a great inspiration to Dangerfield while he was developing his own comedy character. The "Biography" program also tells of the time Benny visited Dangerfield backstage after one of his performances. During this visit Benny complimented him on developing such a wonderful comedy character and style. However, Jack Roy remained Dangerfield's legal name, as he mentioned in several interviews. During a question-and-answer session with the audience on the album No Respect, Dangerfield joked that his real name was Percival Sweetwater.
On Sunday, March 5, 1967, The Ed Sullivan Show needed a last-minute replacement for another act, and Dangerfield became the surprise hit of the show.
Dangerfield began headlining shows in Las Vegas and made frequent encore appearances on The Ed Sullivan Show. He became a regular on The Dean Martin Show and appeared on The Tonight Show a total of 35 times. One of his quips as a standup comedian was, "I walked into a bar the other day and ordered a drink. The bartender says, 'I can't serve you.' I said, 'Why not? I'm over 21!' He said, 'You're just too ugly.' I said as always, 'Boy I tell you, I get no respect around here'." The "no respect" phrase would come to define his act in the years that followed.
In 1969, Rodney Dangerfield teamed up with longtime friend Anthony Bevacqua to build the Dangerfield's comedy club in New York City. Rodney now had a venue in which to perform on a regular basis, without having to constantly travel. The club became a huge success. Dangerfield's has been in continuous operation for over 40 years. Dangerfield's was the venue for several HBO shows which helped popularize many standup comics, including Jerry Seinfeld, Jim Carrey, Tim Allen, Roseanne Barr, Robert Townsend, Jeff Foxworthy, Sam Kinison, Bill Hicks, Rita Rudner, Andrew Dice Clay, Louie Anderson, Dom Irrera and Bob Saget.
His 1980 comedy album, No Respect, won a Grammy Award. One of his TV specials featured a musical number, "Rappin' Rodney", which would appear on his 1983 follow-up album, Rappin' Rodney. In December 1983, the "Rappin' Rodney" single became one of the first Hot 100 rap records, and the associated video was an early MTV hit. The video featured cameo appearances by Don Novello (aka Father Guido Sarducci) as a last rites priest munching on Rodney's last meal of fast food in a styrofoam container and Pat Benatar as a masked executioner pulling a hangman's knot. The two appear in a dream sequence where Dangerfield is condemned to die and doesn't get any respect even in Heaven, as the gates close without his being permitted to enter.
Though his acting career had begun much earlier in obscure movies like The Projectionist (1971), Dangerfield's career peaked during the early 1980s, when he began acting in hit comedy movies.
One of Dangerfield's more memorable performances was in the 1980 golf comedy Caddyshack, in which he played a nouveau riche developer who was a guest at a golf club and began shaking up the establishment of the club's old guard. His role was initially smaller, but because he and fellow cast members Chevy Chase and Bill Murray were so deft at improvisation, their roles were greatly expanded (much to the chagrin of some of their castmates). His appearance in Caddyshack led to starring roles in Easy Money and Back To School. Unlike his stand-up persona, his comedy film characters were portrayed as successful and generally popular—if still loud, brash and detested by the wealthy elite.
Throughout the 1980s, Dangerfield also appeared in a series of commercials for Miller Lite beer, including one where various celebrities who had appeared in the ads were holding a bowling match whose score became tied. After a bearded Ben Davidson told Rodney, "All we need is one pin, Rodney", Dangerfield's ball went down the lane and bounced perpendicularly off the head pin, landing in the gutter without knocking down any of the pins.
In a change of pace from the comedy persona that made him famous, he played an abusive father in Natural Born Killers in a scene for which he wrote or rewrote all of his own lines.
Dangerfield was rejected for membership in the Motion Picture Academy in 1995 by the head of the Academy's Actors Section, Roddy McDowall. After fan protests the Academy reconsidered, but Dangerfield then refused to accept membership.
Dangerfield appeared in an episode of The Simpsons titled "Burns, Baby Burns" wherein he played a character who is essentially a parody of his own persona, Mr. Burns's son Larry Burns. He also appeared as himself in an episode of Home Improvement.
Dangerfield also appeared in the 2000 Adam Sandler film Little Nicky, playing Lucifer, the father of Satan (Harvey Keitel) and grandfather of Nicky (Sandler).
He was recognized by the Smithsonian Institution, which put one of his trademark white shirts and red ties on display. When he handed the shirt to the museum's curator, Rodney joked, "I have a feeling you're going to use this to clean Lindbergh's plane."
Dangerfield played an important role in comedian Jim Carrey's rise to stardom. In the 1980s, after watching Carrey perform at the Comedy Store in Los Angeles, Rodney signed Carrey to open for his Las Vegas show. The two would tour together for about two more years.
Dangerfield was married twice to Joyce Indig. Together, the couple had two children: son Brian Roy (born 1949) and daughter Melanie Roy-Friedman. From 1993 until his death, he was married to Joan Child.
In 1980, Rodney shared an apartment on Manhattan's Upper East Side with a housekeeper, his poodle, Keno, and his closest friend of 30 years, Joe Ancis. Joe was also friend of and major influence on Lenny Bruce, and was a surrealistically fast and funny man who could never perform in front of strangers.
Dangerfield resented being confused with his on-stage persona. Although his wife Joan described him as "classy, gentlemanly, sensitive and intelligent," he was often treated like the loser he played. In his 2004 autobiography, It's Not Easy Bein' Me: A Lifetime of No Respect but Plenty of Sex and Drugs (ISBN 0-06-621107-7), which was released posthumously, he confessed to being a longtime marijuana smoker. The book's original title was My Love Affair With Marijuana.
Although Dangerfield was raised Jewish, he called himself an atheist during an interview with Howard Stern on May 25, 2004. Dangerfield added that he was a "logical" atheist.
On November 22, 2001 (his 80th birthday), Dangerfield suffered a mild heart attack while backstage at the Tonight Show. During Dangerfield's hospital stay, the staff were reportedly upset that he smoked marijuana in his room. But he was back at the Tonight Show a year later, performing on his 81st birthday.
On April 8, 2004, Dangerfield underwent brain surgery to improve blood flow in preparation for heart valve-replacement surgery on August 24, 2004. Upon entering the hospital, he uttered another characteristic one-liner when asked how long he would be hospitalized: "If all goes well, about a week. If not, about an hour and a half."
In September 2004, it was revealed that Dangerfield had been in a coma for several weeks. Afterward, he began breathing on his own and showing signs of awareness when visited by friends. He died on October 5, 2004–a month and a half shy of his 83rd birthday–at the UCLA Medical Center, from complications of the surgery he had undergone in August. Dangerfield was interred in the Westwood Village Memorial Park Cemetery in Los Angeles. His headstone reads, "Rodney Dangerfield... There goes the neighborhood."
Joan Child held an event in which the word "respect" had been emblazoned in the sky, while each guest was given a live monarch butterfly for a butterfly-release ceremony led by Farrah Fawcett.
UCLA's Division of Neurosurgery named a suite of operating rooms after him and gave him the "Rodney Respect Award", which his widow presented to Jay Leno on October 20, 2005. It was presented on behalf of the David Geffen School of Medicine/Division of Neurosurgery at UCLA at their 2005 Visionary Ball. Other such recipients of the "Rodney Respect Award" include Tim Allen (2007), Jim Carrey (2009), Louie Anderson (2010), Bob Saget (2011) and Chelsea Handler (2012).
In his memory, Saturday Night Live ran a short sketch of Dangerfield (played by Darrell Hammond) at the gates of heaven. Saint Peter mentions that he heard Dangerfield got no respect in life, which prompts Dangerfield to spew an entire string of his famous one-liners. After he's done, he asks why Saint Peter was so interested. Saint Peter replies, "I just wanted to hear those jokes one more time" and waves him into heaven, prompting Dangerfield to joyfully declare: "Finally! A little respect!"
On September 10, 2006, Comedy Central's Legends: Rodney Dangerfield commemorated his life and legacy. Featured comedians included Adam Sandler, Chris Rock, Jay Leno, Ray Romano, Roseanne Barr, Jerry Seinfeld, Bob Saget, Jerry Stiller, Kevin Kline and Jeff Foxworthy.
In 2007, a Rodney Dangerfield tattoo was among the most popular celebrity tattoos in the United States.
On The Tonight Show with Jay Leno, May 29, 2009, Leno credited Dangerfield with popularizing the style of joke he had long been using. The format of the joke is that the comedian tells a sidekick how bad something is, and the sidekick—in this case, guitar player Kevin Eubanks—sets up the joke by asking just how bad that something is.
In March 2017, Dangerfield's widow expressed disappointment with a mural that had been painted of Dangerfield in his old New York neighborhood of Queens about a year earlier .
Beginning June 12, 2017, Los Angeles City College Theatre Academy hosted the first class of The Rodney Dangerfield Institute of Comedy. The class is a stand-up comedy class which is taught by comedienne Joanie Willgues, aka Joanie Coyote.