Cooper's father had abandoned the family when he was a baby. A nephew (by marriage) of film director Norman Taurog, he began appearing in short comedy films with Lloyd Hamilton and Bobby Clark when he was three years old. By 1929, he was in the "Our Gang" comedies (then at MGM) and by 1930 had made it in features, co-starring with Janet Gaynor in "Sunny Side Up". "Skippy", which was based on a comic strip character, followed. In the latter, Cooper was a health inspector's son trying to scrape up $3 to buy a dog he has found a license and he was required to cry buckets of tears. The story is told that Taurog tricked the youngster into thinking he had actually killed the dog in real life. Wherever the tears came from, Cooper would turn them on often, earning an Oscar nomination, and appeared in a sequel, "Sooky" (1931). This early period of Cooper's career is also remembered for his work as the loyal son of fallen fighter Wallace Beery in "The Champ" (also 1931), "The Bowery" (1933), as the young nemesis of a saloon-owning Beery, and "Treasure Island" (1934), as Jim Hawkins to Beery's Long John Silver. On screen, the crusty man and the kid with the pouty lower lip had magic. Off screen, Beery showed Cooper no affection whatsoever and resented having to be upstaged by a child.
After he started to age and Roddy McDowall and Freddie Bartholomew took his place as the lads of the day, Cooper began to find himself cast in "B" programmers and even a serial, "Scouts to the Rescue" (1939). Yet, still Cooper proved himself a wonderful screen actor. In "Seventeen" (1940), he was delightful playing an adolescent facing manhood in an adaptation of a Booth Tarkington story. He also did a nice job as a trumpeter in "Syncopation" (1942), but the audience had tired of him. Cooper went into the US Navy for World War II, eventually serving as a captain. When he returned to Hollywood, he was cast in silly fare such as "Killroy Was Here" (1947), about a man trying to lead a normal life when his last name is the same as a running army gag. Within a year, Cooper was without a Hollywood contract for the first time since he was three years old. Not being trained for much else, he elected to continue acting. He took off for New York, where he made his New York stage debut in a 1949 production of "Magnolia Alley" at the Mansfield Theatre. Soon after, he toured the country as Ensign Pulver in "Mr. Roberts" and played the role in the London production in 1951. More stage work followed, but no film offers. So Cooper turned to TV. By 1952, he was a frequent player on anthology episodics, and in 1955, he helped put together his first series, "The People's Choice", for NBC, on which he also served as producer and director of many of show's episodes during its 1955-58 run. He played a naturalist who had been elected to his community's city council and took government seriously. A gimmick of the show was that his basset hound, Cleo, spoke--but only to the audience and only through thoughts. "The People's Choice" was successful, but canceled prematurely, and Cooper went into another series "Hennesey" (CBS, 1959-62), in which he was a young medical officer in the Navy. Again, Cooper served as star, producer and director, but "Hennesey" did not fare as well with critics. After its demise, he made guest appearances.
In 1964, Cooper was asked to become vice president of program development for Columbia Pictures' TV division (formerly Screen Gems). He accepted the post and for five years was responsible for packaging series (such as "Bewitched") and other projects and selling them to the networks. He seemed to thrive at this job, acting only once during this period, in his TV-movie debut "Shadow on the Land" (ABC, 1968). Cooper left Columbia in 1969 and started yet another phase of his career, one in which he would act occasionally in key character roles, but mostly he devoted more and more of his time to directing episodic TV and other projects. One of his first acting projects after returning to SAG jurisdiction was in the TV-movie "Maybe I'll Come Home in the Spring" (ABC, 1971), in which Cooper and Eleanor Parker were the parents of teen-age runaway Sally Field who returns home to find that while she loves her parents, the very hypocrisy of their world has not changed. It was, at the time, cutting edge TV for a medium which since the 50s had been afraid to tackle socially relevant subject matter. Cooper hosted "The Dean Martin Comedy World" (NBC, 1974) and in 1975 he took one last stab at TV series regular acting with "Mobile One" (ABC), in which he was a veteran news reporter.
One of Cooper's first feature film acting jobs in his post-executive period was "The Love Machine" (1971), in which he was a boot-licking TV programming executive. In 1972, he directed his first feature, "Stand Up and Be Counted", with Jacqueline Bisset as a writer who returns to her home town. The film was touted as feminist, although it did not fare well at the box office. But while Cooper continued to act in an occasional episodic through the 1980s, and in the occasional feature film, his chief career from 1972 on was directing, particularly TV pilots and episodics. He directed 13 episodes of CBS' groundbreaking "M*A*S*H" during the 1973-74 season, earning an Emmy for his work. He went on to direct "The Mary Tyler Moore Show" (1974) and won a second Emmy for the 1978 pilot of "The White Shadow", starring Ken Howard. Other credits include multiple episodes of such series as "Lou Grant", "The Black Sheep Squadron", "Cagney and Lacey", "Magnum, P.I." and "Quincy". He branched out to longforms, including "Rainbow" (NBC, 1978), a biopic of the young Judy Garland, and "Rosie: The Rosemary Clooney Story" (CBS, 1982). Cooper announced his retirement in 1989, although he was still directing episodes of the syndicated series "The Adventures of Superboy". He began spending more time raising horses at his home outside San Diego. He occasionally returned to the soundstage for retrospective and documentary programs about Hollywood in which he had toiled for the entire sound period to-date, and even some silent films.