Karen Carpenter was born in New Haven, Connecticut, the daughter of Agnes Reuwer (née Tatum) and Harold Bertram Carpenter. When she was young, she enjoyed playing baseball with other children on the street. On the TV program This Is Your Life, she stated that she liked pitching. Later, in the early 1970s, she would become the pitcher on the Carpenters’ official softball team. Her brother Richard developed an interest in music at an early age, becoming a piano prodigy. The family moved in June 1963 to the Los Angeles suburb of Downey.  When Carpenter entered Downey High School, she joined the school band. Bruce Gifford, the conductor (who had previously taught her older brother) gave her the glockenspiel, an instrument she disliked. After admiring the performance of her friend, Frankie Chavez, she asked if she could play the drums instead. She and her brother made their first recordings in 1965 and 1966. The following year she began dieting. Under a doctor’s guidance she went on the Stillman Diet. She rigorously ate lean foods, drank eight glasses of water a day, and avoided fatty foods. She was 5′ 4″ (163 cm) in height and before dieting weighed 145 pounds (66 kg; 10 st 5 lb) and afterwards weighed 120 pounds (54 kg; 8 st 8 lb) until 1973, when the Carpenters’ career reached its peak. By September 1975, her weight was 91 pounds (41 kg; 6 st 7 lb).

From 1965 to 1968 Karen, her brother Richard, and his college friend Wes Jacobs, a bassist and tuba player, formed The Richard Carpenter Trio. The band played jazz at numerous nightclubs and also appeared on the TV talent show Your All-American College Show. Karen, Richard and other musicians, including Gary Sims and John Bettis, also performed as an ensemble known as Spectrum. Spectrum focused on a harmonious and vocal sound, and recorded many demo tapes in the garage studio of friend and bassist Joe Osborn. Many of those tapes were rejected. According to former Carpenters member John Bettis, those rejections “took their toll.” The tapes of the original sessions were lost in a fire at Joe Osborn’s house, and the surviving versions of those early songs exist as acetate pressings.  Finally A&M Records signed the Carpenters to a recording contract in 1969. Karen sang most of the songs on the band’s first album, Offering (later retitled Ticket to Ride), and her brother wrote 10 out of the album’s 13 songs. The issued single (later the title track), which was a cover of a Beatles song, became their first single; it reached #54 on the Billboard Hot 100. Their next album, 1970’s Close to You, featured two massive hit singles: “(They Long to Be) Close to You” and “We’ve Only Just Begun”. They peaked at #1 and #2, respectively, on the Hot 100.

Carpenter started out as both the group’s drummer and lead singer, and she originally sang all her vocals from behind the drum set. Because at 5 feet 4 inches tall it was difficult for people in the audience to see her behind her drum kit, she was eventually persuaded to stand at the microphone to sing the band’s hits while another musician played the drums. (Former Disney Mouseketeer Cubby O’Brien served as the band’s other drummer for many years.) After the release of Now & Then in 1973, the albums tended to have Carpenter singing more and drumming less. At this time her brother developed an addiction to Quaaludes. The Carpenters frequently cancelled tour dates, and they stopped touring altogether after their September 4, 1978, concert at the MGM Grand in Las Vegas. The Carpenters’ Very First TV Special was Richard and Karen Carpenter’s very first television special, aired December 8, 1976. In 1980, she performed a medley of standards in a duet with Ella Fitzgerald on the Carpenters’ television program Music, Music, Music. In 1981 after the release of the Made in America album (which turned out to be their last), the Carpenters returned to the stage and did some tour dates, including their final live performance in Brazil.

In addition to being a drummer and a singer, Karen Carpenter could also play the electric bass guitar . She played bass guitar on two songs on Offering/Ticket to Ride (the Carpenters first album released by A&M). The two songs were All of My Life and Eve. Although Karen’s guitar playing is heard on the original album(s), Richard remixed both songs (as he has done with almost every Carpenters song), and Joe Osborne’s guitar playing was substituted for later ‘greatest hits’ releases.

Carpenter started playing the drums in 1964. She was always enthusiastic about the drums and taught herself how to play complicated drum lines with “exotic time signatures,” according to her brother. Carpenter’s drumming was praised by fellow drummers Hal Blaine, Cubby O’Brien, and Buddy Rich and by Modern Drummer magazine. According to her brother, Carpenter always considered herself a “drummer who sang.” Despite this, she was not often featured as a drummer on the Carpenters’ albums. She was, however, the only drummer on the album Ticket to Ride and on the songs “Mr. Guder” and “Please Mr. Postman.” The role of drummer in the Carpenters entourage was mainly taken over by Hal Blaine as she went from behind the drum set to the front of the stage.

In 1979 Richard took a year off to cure his dependency on Quaaludes, and Karen decided to make a solo album with producer Phil Ramone. Her solo work was markedly different from usual Carpenters fare, consisting of adult-oriented and disco/dance-tempo material with more sexual lyrics and the use of Karen’s higher vocal register. The project met a tepid response from Richard and A&M executives in early 1980. The album was shelved by A&M CEO Herb Alpert, in spite of Quincy Jones’ attempts to talk Alpert into releasing the record after some tracks had been remixed. A&M made the Carpenters pay $400,000 to cover the cost of recording Karen’s unreleased solo album to be charged against the duo’s future royalties. Carpenters fans got a taste of the album in 1989 when some of its tracks (as remixed by Richard) were mixed onto the album Lovelines, the final album of Carpenters’ new unreleased material. In 1996 the completed album, titled Karen Carpenter, featuring mixes approved by Karen before her death and one unmixed bonus track, finally was released.

Carpenter lived with her parents until she was 26. After the Carpenters became successful in the early 1970s, she and her brother bought two apartment buildings in Downey as a financial investment. Formerly named the “Geneva”, the two complexes were renamed “Only Just Begun” and “Close to You” in honor of the duo’s first smash hits. The apartment buildings are located at 8353 and 8356 (respectively) 5th Street, Downey, California. In 1976 Carpenter bought two Century City apartments, gutted them, and turned them into one condominium. Located at 2222 Avenue of the Stars, the doorbell chimed the first six notes of “We’ve Only Just Begun”. As a housewarming gift, her mother gave her a collection of leather-bound classic works of literature. Carpenter collected Disney memorabilia, loved to play softball and baseball, and counted Petula Clark, Olivia Newton-John and Dionne Warwick among her closest friends.

Carpenter dated a number of well-known men, including Mike Curb, Tony Danza, Terry Ellis, Mark Harmon, Steve Martin and Alan Osmond. After a whirlwind romance, she married real-estate developer Thomas James Burris on August 31, 1980, in the Crystal Room of the Beverly Hills Hotel. Burris, divorced with an 18-year-old son, was nine years her senior. A new song performed by Carpenter at the ceremony, “Because We Are in Love”, was released in 1981. Burris concealed from Carpenter, who desperately wanted children, the fact that he had undergone a vasectomy. Their marriage did not survive the deceit and ended after 14 months.

“Now”, recorded in April 1982, was the last song Carpenter recorded. She recorded it after a two-week intermission in her therapy with psychotherapist Steven Levenkron in New York City for her anorexia, during which she had lost a considerable amount of weight. During her illness, in order to lose weight, she had taken thyroid replacement medication (to speed up her metabolism) and laxatives. Despite her participation in therapy, her condition continued to deteriorate and she only lost more weight, leading Carpenter to call her psychotherapist to tell him she felt dizzy and that her heart was beating irregularly. Finally in September 1982, she was admitted to Lenox Hill Hospital in New York and hooked up to an intravenous drip, which caused her to gain a considerable amount of weight (30 pounds) in just eight weeks. The sudden weight gain further strained her heart, which was already weak from years of dietary restriction.

Carpenter returned to California in November 1982, determined to reinvigorate her career, finalize her divorce, and begin a new album with Richard. On December 17, 1982, Karen gave her last singing performance in the multi-purpose room of the Buckley School in Sherman Oaks, California, singing Christmas carols for her godchildren, their classmates who attended the school, and other friends. On January 11, 1983, Karen made her last public appearance at a photocall of past Grammy Award winners to celebrate the award’s 25th anniversary. Karen appeared somewhat frail and worn out but according to Dionne Warwick, she was vibrant and outgoing, exclaiming to everyone, “Look at me! I’ve got an ass!”

On February 4, 1983, less than a month before her 33rd birthday, Carpenter suffered heart failure at her parents’ home in Downey, California. She was taken to Downey Community Hospital, where she was pronounced dead 20 minutes later. The Los Angeles coroner gave the cause of death as “heartbeat irregularities brought on by chemical imbalances associated with anorexia nervosa.” Under the anatomical summary, the first item was heart failure, with anorexia as second. The third finding was cachexia, which is extremely low weight and weakness and general body decline associated with chronic disease. Her divorce was scheduled to have been finalized that day. The autopsy stated that Carpenter’s death was the result of emetine cardiotoxicity due to anorexia nervosa, revealing that she had poisoned herself with ipecac syrup, an emetic often used to induce vomiting in cases of overdosing or poisoning. Carpenter’s use of ipecac syrup was later disputed by Agnes and Richard, who both stated that they never found empty vials of ipecac in her apartment and have denied that there was any concrete evidence that she had been vomiting. Richard has also expressed that he believes Karen was not willing to ingest ipecac syrup because of the potential damage that both the syrup and excessive vomiting would do to her vocal cords and that she relied on laxatives alone to maintain her low body weight.

Carpenter’s funeral service took place on February 8, 1983, at the Downey United Methodist Church. Dressed in a rose-colored suit, Carpenter lay in an open white casket. Over 1,000 mourners passed through to say goodbye, among them her friends Dorothy Hamill, Olivia Newton-John, Petula Clark, and Dionne Warwick. Carpenter’s estranged husband Tom attended her funeral, where he took off his wedding ring and placed it inside the casket. She was entombed at the Forest Lawn Memorial Park in Cypress, California. In 2003, Richard Carpenter had Karen re-interred, along with their parents, in the Carpenter family mausoleum at the Pierce Brothers Valley Oaks Memorial Park in Westlake Village, California, which is closer to his Southern California home.