Curly Howard joined the Three Stooges in 1932 when oldest brother Shemp Howard left to pursue a solo career. At first, he was thought to be too handsome to be a Stooge by Ted Healy. One of the conditions for joining the team was that he had to shave off his mustache and wavy hair. He did, but insisted on being called "Curly". Later, the act moved to the movie screen.

In 1934, Curly began to star as a Stooge in 97 two-reel comedies for Columbia Pictures. However, success destroyed Curly. He began to drink heavily, feeling that his shaven head robbed him of his sex appeal. Curly wore a hat in public to confirm an image of masculinity, saying he felt like a little kid with his hair shaved off. Curly had difficulties managing his finances. When he received a paycheck, he would rush out to spend it on wine, food, women, a new house, an automobile or a new dog.

Curly was not a businessman and Moe usually handled all of his affairs, helped him manage his money, and even completed his income tax returns. Since income from his successful career was carelessly spent, Curly was often left near the poverty level. He was married four times, including a youthful marriage which was annulled in six months.

Curly's homes were in the San Fernando Valley. One house Curly purchased from child star Sabu was on Cahuenga Boulevard and Sarah Street in North Hollywood. Later, Curly sold the property to a promising young actress of the 1940s, Joan Leslie. Curly also bought a lot next door to Moe Howard's palatial home in Toluca Lake, expecting to build on it, but never did. It was eventually sold to film director Raoul Walsh.

Curly was an introvert who barely spoke on the set between takes. Charles Lamont, who directed Curly in two Stooges comedies, related in an interview that "Curly was pretty dull. This may not be a very nice thing to say but I don't think he had all of his marbles. He was always on Cloud Nine whenever you talked to him."

Clarice Seiden, the sister of Helen Howard, Moe's wife, saw Curly off screen whenever there was a party at his home. She remembers him as being far from "a quiet person." Seiden said: "Although he wasn't on (stage) all the time, I wouldn't call him a quiet person. ... he was a lot of fun. He was quiet at times but when he had a few drinks-and he drank quite a bit-he was more gregarious."

Curly refrained from crazy antics in private life. He reserved them for his performances in the comedies. When he got together with his brothers, he came out of his shell.

Curly's main weakness was women. He married three times after his first marriage was annulled. The identity of his first wife was a closely guarded secret and has now been lost to history. On June 7, 1937, he married Elaine Ackerman. In 1938, Elaine gave birth to Curly's first child, Marilyn. Due to the addition to their family, Curly and Elaine moved to a home on the 400 block of Highland Avenue in Hollywood, near where Moe lived at the time. Elaine filed suit for divorce on July 11, 1940, after only three years of marriage.

During the next five years, Curly ate, drank, and made merry to the extreme. He gained a tremendous amount of weight and his blood pressure soared. By January 1945, his physical and mental health bottomed out. He suffered a minor stroke at age 42, the effects which are apparent in the 1945 short If A Body Meets A Body.

He lost weight, was often sedated from taking heavy meds, and, at times, looked lethargic. His failing health came to a head on May 6th, 1946, when he suffered a major stroke on the set of the short Half-Wits' Holiday (1947). Curly was rushed to the hospital, and eventually he had to retire from the Stooges. After another stroke in 1949, he was confined to a wheelchair.

After several additional strokes, Curly Howard died in San Gabriel, California on January 18, 1952.