Krim received his primary and secondary education in Mount Vernon, NY. In January 1923, he entered Mt. Vernon High School and graduated in 1927. His high school extracurricular activities included the presidency of the graduating class, captaincy of the cross-country team, member of the track team, valedictorian of his class, membership on the editorial board of the school magazine, and the presidency of the debating society.

Shortly after law school graduation, Krim joined Phillips and Nizer, specializing in entertainment law. Admitted to the New York bar in 1933, he became partner in 1935, and the firm was renamed Phillips, Nizer, Benjamin, Krim and Ballon. In the 1930s, Krim prospered, representing many theater artists and writers, such as the playwright Clifford Odets (1906–1963) and the actor John Garfield (1913–1952), who were members of the Group Theatre (1931–1941). It was his association with the Group that nurtured his innate empathy for the artistic temperament and understanding of the creative community.

In 1940, Krim started his first job in the film business with the National Screen Service (NSS). From about 1940 until the 1980s, the NSS, headquartered in Englewood, New Jersey, controlled the distribution of theatrical advertising throughout the United States. He departed from NSS in 1942 in order to enlist in the U.S. Army (1942–1945).

In 1978, Krim became of counsel. In this regard, being of counsel meant that he kept an office at the firm's New York City headquarters and continued to be a highly esteemed permanent adviser.

In 1946, Krim became the head of Eagle-Lion Films, a low-budget production venture led by the British film mogul J. Arthur Rank (1888–1972) and the American financier Robert Young (1897–1958). After a severe financial downturn in 1947, Krim took over as studio chief and changed its mode of production, using more independent producers as a source for new films. Eagle-Lion would help finance the films and offer facilities. Under this formula, they began producing lower-budget films and enjoyed particular success with film noir. Clashing repeatedly with Young, however, Krim resigned in 1949.

The United Artists Corporation (UA) was established in 1919 by the following individuals: film director D.W. Griffith (1875–1948), English comic actor, filmmaker, and composer Charlie Chaplin (1889–1977), actress, producer, and screenwriter Mary Pickford (1892–1979), and actor and filmmaker Douglas Fairbanks, Sr. (1883–1939). UA was founded on the idea that actors should have control over their careers rather than be dependent on commercial studios.

However, by 1950, United Artists was on the verge of financial collapse. In February 1951, a group led by Arthur Krim and Robert Benjamin (1909–1979), who had overseen the American operations of the Arthur Rank Organization, made a deal with Pickford and Chaplin to give them control of the company by securing a $3 million loan from Fox Film Corporation president Spyros Skouras (1893–1971). As per the terms of the agreement, UA would acquire half of the company's stock if they generated a profit within three years. They accomplished this in six months, with Krim serving as president and Benjamin as chairman, roles they retained until 1968. By 1956, they had bought out Chaplin and Pickford. United Artists went public in 1957 with a $17 million stock and debenture offering.

In their takeover of UA, Krim and Benjamin would create the first studio without an actual "studio." Acting primarily as bankers, who, in exchange for financing, gave unprecedented levels of creative autonomy to independent producers, directors, actors, and writers—some of whom had been blacklisted during the McCarthy era. Krim gained notoriety for bankrolling obscure and distinctive filmmakers, producers, or writers who either could not or would not fit into the Hollywood mold but had compelling tales to tell.

Since they did not own a studio lot, UA did not have the high overhead, the maintenance costs, or the expensive production staff of other film companies. Under this innovative model, the UA would produce, on average, 50 films per year. Throughout the 1950s, Krim brought UA back with such critical cinematic triumphs as (1951), (1952), (1955), and (1957). By 1958, UA was turning a $3 million profit annually.

In the 1960s, UAs success continued with such diverse movies as: (1961); (1963); (1964); (1965); the James Bond franchise, and the spaghetti westerns (1964); and (1966); (1967); and (1967).

The seventies commenced with such achievements as the screen version of Fiddler on the Roof (1971) and Woody Allen's (1971). In 1975, UA released , which won the Best Picture Academy Award. UA followed with the next two years' Best Picture Oscar winners, (1976) and (1977), becoming the first studio to not only win the award for three years running but also become the studio with the most Best Picture winners at that time.

On April 8, 1975, at the 47th Academy Awards, the singer Frank Sinatra (1915–1998) presented Arthur Krim with the Jean Hersholt Humanitarian Award of The Academy of Motion Picture Arts and Sciences (AMPAS). The AMPAS periodically confers the Hersholt Award to recognize an individual for their "outstanding contributions to humanitarian causes."

In the late 1970s, however, conflicts arose with the management of Transamerica Corporation, which had acquired United Artists in 1967. As a result, Krim, Benjamin, and three other studio executives—Eric Pleskow (1924–2019), Mike Medavoy, and William Bernstein (1933–2020)—resigned from United Artists and founded Orion Pictures in January 1978.

In January 1978, Krim, Benjamin, Eric Pleskow, Mike Medavoy, and William Bernstein organized Orion Pictures with Krim as chairman (1978–1992).

At Orion Pictures, he and his team continued the same successful approach. Orion's most notable films include (1984), (1986), (1986), (1990), and (1991).

Krim served as a director on the following corporate boards: Occidental Petroleum Corporation and its subsidiary companies Oxy Oil and Gas Company, and Iowa Beef Products, Inc.

Arthur Krim was a director on many non-corporate boards, including the following three organizations represented alphabetically in this subseries: the African-American Institute (Life Trustee), the Armand Hammer United World College of the American West, and the Arms Control Association.

Krim was also a prominent director of the Weizmann Institute of Science. Although this collection does not contain any correspondence or documents related to Krim's board work, materials concerning the charitable events and honorary dinners of the Institute are located in Series VII: Photographs, 1912–1994, and Series VIII: Subject Files, 1942–1995.

In 1962, President John F. Kennedy established The President's Club of New York in an effort to close the campaign deficit from the 1960 election. As chairman of the Democratic National Finance Committee (1966–1968), Arthur Krim also led the president's club (1962–1968) on behalf of Presidents Kennedy and Lyndon B. Johnson. The club operated as a political fund-raising entity under Krim's direction, with the Democratic National Committee receiving the majority of the funds.

In May 1968, Arthur Krim was appointed by President Lyndon Johnson "Special Consultant to the President of the United States", a post he held until January 20, 1969.

From 1973 to 1976, Krim chaired the Democratic Advisory Council of Elected Officials (DACEO), which was established by Robert S. Strauss (1918–2014), the Democratic National Committee chairman (1972–1977), who wanted to keep the group closed to outside influence and charge members with formulating public positions on foreign and domestic policy matters.

By appointment of the President and consent of the Senate, Krim served on the General Advisory Committee (1977–1988), which, by statute, advised the President and the Secretary of State in matters pertaining to arms control. The committee sought to provide a comprehensive historical basis for understanding and anticipating the conduct of the Soviet Union related to compliance with arms control commitments.