Switzer was born in Paris, Illinois, the second son, fourth and last child of Gladys C. Shanks and George Frederick Switzer. He was named Carl after the Switzer family and Dean after many relatives in his grandmother's family. He and his older brother, Harold, became famous around their hometown for their musical talent and performances; both sang and played a number of instruments.
In 1934. the Switzers took a trip to California to visit with family members. While sightseeing they eventually wound up at Hal Roach Studios. Following a public tour of the facility, 8-year-old Harold and 6-year-old Carl entered into the Hal Roach Studio's open-to-the-public cafeteria, the Our Gang Café, and began an impromptu performance. Producer Hal Roach was present at the commissary that day and was impressed. He signed both Switzers to appear inOur Gang. Harold was given two nicknames, "Slim" and "Deadpan," and Carl was dubbed "Alfalfa."
The Switzer brothers first appeared in the 1935 Our Gang short, Beginner's Luck. By the end of the year, Alfalfa was one of the main characters in the series, while Harold had more or less been relegated to the role of a background player. Although Carl Switzer was an experienced singer and musician, his character Alfalfa was often called upon to sing off-key renditions of pop standards and contemporary hits, most often those of Bing Crosby. Alfalfa also sported cowlicks.
By the end of 1937, Switzer had supplanted George "Spanky" McFarland, the series' nominal star, in popularity. While the two boys managed to get along, their fathers fought and argued constantly over their sons' screen times and salaries. Switzer's best friend among the Our Gang kids was Tommy Bond, who played his on-screen nemesis "Butch". In Bond's words, he and Switzer became good friends because "neither of us could replace the other since we played opposites." Switzer was known for being abrasive and difficult on the set. He would often play cruel jokes on the other children and would hold up filming with his antics.
The production rights for Our Gang were sold to Metro-Goldwyn-Mayer in 1938, and the first two years' worth of MGM-produced series entries focused heavily on the Alfalfa character and his family.
Switzer's tenure on Our Gang ended in 1940, when he was twelve. His first role after leaving the series was as co-star in the 1941 comedy Reg'lar Fellers. The next year, he had a supporting role in Mrs. Wiggs of the Cabbage Patch. Switzer continued to appear in films in various supporting roles, including in Johnny Doughboy (1942), Going My Way (1944), and The Great Mike (1944). Switzer had an uncredited role as Auggie in the 1943 film The Human Comedy. Switzer's last starring roles were in a brief series of imitation-Bowery Boys movies; he reprised his "Alfalfa" character, complete with comically sour vocals, in PRC's Gas House Kids comedies of 1946 and 1947. By this time in his career Switzer was downplaying his earlier Our Gang work; in his 1946 resume he referred to the films generically as "M-G-M short product."
In 1946, Switzer had a small part in the 1946 Christmas film It's a Wonderful Life as Mary Hatch's (Donna Reed) date at the high school dance in the beginning of the film. In the 1954 musical filmWhite Christmas, his picture is used to depict an Army buddy (named "Freckle-Faced Haynes") of lead characters Wallace and Davis (played by Bing Crosby and Danny Kaye), and also the brother of the female leads the Haynes Sisters (played by Rosemary Clooney and Vera-Ellen).
In the 1950s, Switzer turned to television. From 1952 to 1955, he made six appearances on The Roy Rogers Show. He also guest-starred in an episode of the American science fiction anthology series Science Fiction Theatre, and The George Burns and Gracie Allen Show. In 1953 and 1954, Switzer co-starred in three William A. Wellman-directed films: Island in the Sky and The High and the Mighty, both starring John Wayne, and Track of the Cat starring Robert Mitchum. In 1956, he co-starred in The Bowery Boys film Dig That Uranium, followed by a bit part as a Hebrew slave in Cecil B. DeMille's The Ten Commandments. Switzer's final film role was in the film drama The Defiant Ones.
In addition to acting, Switzer bred and trained hunting dogs and guided hunting expeditions. Among his more notable clients were Roy Rogers and Dale Evans (Switzer's son's godparents), James Stewart and Henry Fonda.
In early 1954, Switzer was set up on a blind date with Diantha (Dian) Collingwood (November 19, 1930–November 29, 2004), the heiress of grain elevator empire Collingwood Grain. Collingwood had moved with her mother and sister to California from Hutchinson in 1953 because her sister wanted to become an actress. Switzer and Collingwood were married in Las Vegas three months later. In 1956, with money running dry and Dian pregnant, her mother offered her and Switzer a farm north of Pretty Prairie, west of Wichita. A son, Justin Lance Collingwood Switzer (now Eldridge), was born early that year in Garden City. The couple was divorced in 1957.
The last time I saw Carl was 1957. It was a tough time for me—and him. I was starting a tour of theme parks and county fairs in the Midwest. Carl had married this girl whose father owned a pretty good size farm near Wichita. When I came through town, he heard about it and called. He told me he was helping to run the farm, but he finally had to put a radio on the tractor while he was out there plowing. Knowing Carl, I knew that wasn't going to last. He may have come from Paris, Illinois, but he wasn't a farmer! We hadn't seen each other since we left the 'Gang.' So we had lunch; we talked—about all the things you'd expect. And then I never saw him again. He looked pretty much the same. He was just Carl Switzer—kind of cocky, a little antsy—and I thought to myself he hadn't changed that much. He still talked big. He just grew up. — George McFarland
In January 1958, Switzer was getting into his car in front of a bar in Studio City when a bullet smashed through the window and struck him in the upper right arm. The perpetrator was never caught. In December of that year, Switzer was arrested in Sequoia National Forest for cutting down 15 pine trees. He was sentenced to a year's probation and ordered to pay a $225 fine.
Prior to a hunting guide job, Switzer agreed to train a hunting dog for Moses Samuel "Bud" Stiltz. After the dog was lost, having run after a bear, Switzer offered a $50 reward for the dog's return. A man found the dog a few days later and brought it to the Studio City bar where Switzer was working. Switzer paid the man $35 and bought him $15 worth of drinks from the bar. Several days later, on the evening of January 21, 1959, Switzer and his friend, 37-year-old unit still photographer Jack Piott, came to the conclusion that Stiltz owed Switzer the $50 paid to the man who found the dog. Shortly before 7:00 p.m. that evening, the pair arrived at Rita Corrigan's home in Mission Hills, where Stiltz was staying, to collect the money Stiltz "owed" Switzer.
According to Stiltz's testimony, he banged on his front door, demanding, "Let me in, or I'll kick in the door." Once Switzer was inside the home, he and Stiltz got into an argument. Switzer informed Stiltz that he wanted the money owed him, saying "I want that 50 bucks you owe me now, and I mean now." When Stiltz refused to hand over the money, the two engaged in a fight. Switzer allegedly struck Stiltz in the head with a glass-domed clock, which caused him to bleed from his left eye. Stiltz retreated to his bedroom and returned holding a .38-caliber revolver, but Switzer immediately grabbed the gun away from him, resulting in a shot being fired that hit the ceiling. Switzer then forced Stiltz into a closet, despite Stiltz having gotten his hands back on the gun. Switzer then allegedly pulled a switchblade knife and screamed, "I'm going to kill you" and was attempting to stab him with it, but just as Switzer was about to charge Stiltz, Stiltz raised the gun and shot Switzer in the groin. Switzer suffered massive internal bleeding and was pronounced dead on arrival at the hospital.
Carl Switzer is interred at the Hollywood Forever Cemetery in Hollywood, California. Switzer died on the same day as Cecil B. DeMille. Switzer received only minor footnotes in most newspapers, while DeMille's obituary dominated the columns.