William S. Paley was born on September 28, 1901, in Chicago, Illinois. The elder of two children, Paley grew up in a traditional American household. His father, Samuel Paley, was a Ukrainian Jewish immigrant who founded a successful cigar business, while his mother, Goldie, raised him and his younger sister. In 1918, Paley graduated from the Western Military Academy in Alton, Illinois, and in 1919, he was admitted into the University of Chicago. While attending the University of Chicago, Paley's father was confronted with the arduous task of expanding his cigar business to Philadelphia, Pennsylvania. With the new expansion, Samuel Paley moved his family to Philadelphia.

While in Philadelphia, William S. Paley continued his education at the University of Pennsylvania's Wharton School of Finance. In 1922, he graduated from the University of Pennsylvania with a Bachelor of Science in finance, and he became the production and marketing manager at his father's Congress Cigar Company. In 1923, under his father's guidance, Paley was named vice president of the cigar company, and in 1925, he was named the company's secretary.

While on a business trip in Europe in 1926, Paley was alerted to the profit potential in radio broadcasting. In August 1928, he was given the option to purchase a struggling company in the broadcasting field, the United Independent Broadcasters (UIB). Although the company was a risky investment, it generated a great deal of interest for Paley. After careful consideration, he purchased UIB on September 25, 1928, for $400,000. In 1929, Paley changed the name of United Independent Broadcasters to the Columbia Broadcasting System (CBS), and later that year, he expanded the company's radio stations to reach the Pacific Coast. Under Paley's leadership, CBS turned into one of the most successful radio broadcasting companies in the world. By 1930, CBS controlled over 70 radio stations, and on February 4, 1930, Paley introduced the first educational radio broadcast, the Columbia School of the Air.

In 1932, Paley married Dorothy Hart Hearst, with whom he had one son and one daughter. In 1936, CBS introduced the first successful worldwide news broadcast, The Columbia Workshop, and in 1937, it broadcasted its first foreign language program to South America. During the late 1930s, Paley initiated the fight against radio censorship, and he denied the Federal Communications Commission's accusation of controlling a radio broadcasting monopoly. In 1938, The New York Times published an article stating that Paley "urged close public scrutiny of all proposals tending toward censorship of radio broadcasting, the vesting of program control in any regulatory authority or the undermining of the American system of private competitive operation." Paley's fight against radio censorship intensified during the early 1940s, when he insisted that CBS grow into the worldwide leader of providing unrestricted broadcasting of World War II.

In early 1943, Paley named Paul Keston the new acting president of CBS, while he traveled to Europe to work on Italian and North African radio broadcasting networks. In 1945, he became a colonel in the United States Armed Forces and was appointed the acting Deputy Chief of Psychological Warfare under the command of General Dwight D. Eisenhower. After the war ended in 1945, Paley was recognized for his outstanding service in the United States Armed Forces. In November 1945, he received the Medal for Merit, and in March 1946, he received the prestigious Legion of Merit. Shortly after, Paley also received the Legion of Honor and the Croix de Guerre with Palm, the highest honors that France can bestow.

When Paley returned home in late 1945, he restructured the Columbia Broadcasting System. In 1945, he appointed himself Chairman of the Board, and in January 1946, he named Frank Stanton the new president of CBS. In 1947, while restructuring CBS, Paley divorced Dorothy Hart Hearst and married Barbara Cushing Mortimer, a famous American fashion icon. He had another two children with Mortimer, again one son and one daughter. In the early 1950s, Paley promoted Edward R. Murrow to one of the head newscasters of CBS. Murrow enthusiastically appeared in closing segments of the CBS Evening News in 1950, quickly earning the attention and respect of nearly every American. In 1951, Paley introduced the Emmy Award-winning television show See It Now, which was also hosted by Murrow. In 1955, CBS broadcasted The $64,000 Question, the most popular game show on television at the time. Although the show was a success, The $64,000 Question was later consumed in the "Quiz Show Scandal" of the 1950s that ravaged the entire broadcast industry, and it was cut by CBS. In the early 1960s, Paley introduced the idea of television specials. One of his most successful specials included taking the American public on a televised tour of the White House, hosted by former First Lady Jackie Kennedy. In 1966, CBS began to broadcast all of its programs in color. Not surprisingly, under the leadership of Paley and Stanton, CBS led the prime-time broadcasting ratings from 1955 through 1976.

In 1964, Paley purchased the New York Yankees for $11.2 million from Dan Topping and Del Webb. The Yankees had nine disappointing seasons under the control of William S. Paley, since he dedicated the majority of his time to CBS's success and thus never intervened in the team's affairs. On January 3, 1973, Paley sold the New York Yankees to George Steinbrenner for $10 million.

In 1976, William Paley founded the Museum of Television and Radio in New York City. In 1977, he stepped down as the chief executive officer of CBS, and in 1979, he published a record of his lifetime achievements, entitled As It Happened: A Memoir. In 1980, Paley named Thomas Wyman the new president of CBS, and in 1983, he asked Wyman to replace him as Chairman of the Board. Unimpressed with Wyman's actions as the chief executive officer and Chairman of the Board, Paley ousted Wyman in 1986 and hired Lawrence Tisch as the new chief executive officer. In 1986, Paley returned as Chairman of the Board of CBS, a position that he held until he died from kidney failure on October 26, 1990, in New York, New York.

Today, William S. Paley is recognized as one of the founding fathers of radio broadcasting. Christopher H. Sterling, writing on behalf of The Museum of Broadcast Communications, described Paley as being most important for assembling the team that built and expanded CBS. The Columbia Broadcasting System is currently worth over $20 billion, and it is one of the most successful corporations in the world. Paley is honored at the Museum of Television and Radio, where the commemorative William S. Paley Festival is held annually.