Mayer was born possibly Lazar Meir to a Jewish family in Dymer, Russian Empire (now Ukraine). According to his personal details in the U.S. immigration documents, the date was 4 July 1885; according to some studies based on the March 1901 Canada census, the date may have been 12 July 1884. In addition he gave his birth year as 1882 in his marriage certificate while the April 1910 census states his age as 26 (b.1883). His parents were Jacob Meir and Sarah Meltzer and he had two sisters—Yetta, born in c. 1878 and Ida, born in c. 1883. Mayer first moved with his family to Long Island, where they lived from 1887 to 1892 and where his two brothers were born—Rubin, in April 1888 and Jeremiah, in April 1891. Then, they moved to Saint John, New Brunswick, where Mayer attended school.

In his spare time, he hung around the York Theater, sometimes paying to watch the live vaudeville shows. He became enamored with the entertainment business. Then in 1904 the 20-year-old Mayer left Saint John for Boston, where he continued for a time in the scrap metal business, got married and took a variety of odd jobs to support his new family when his junk business lagged.

Mayer renovated the Gem Theater, a rundown, 600 seat burlesque house in Haverhill, Massachusetts, which he reopened on November 28, 1907 as the Orpheum, his first movie theater. To overcome an unfavorable reputation that the building had, Mayer opened with a religious film at his new Orpheum, From the Manger to the Cross, in 1912. Within a few years, he owned all five of Haverhill’s theaters, and, with Nathan H. Gordon, created the Gordon-Mayer partnership that controlled the largest theater chain in New England. During his years in Haverhill, Mayer lived on 16 Middlesex St. in the city’s Bradford section, closer to city center on Temple Street and at 2 1/2 Merrimac St. Mayer also lived in a house he built at 27 Hamilton Ave.

In 1914, the partners organized their own film distribution agency in Boston. Mayer paid D.W. Griffith $25,000 for the exclusive rights to show The Birth of a Nation (1915) in New England. Although Mayer made the bid on a film that one of his scouts had seen, but he had not, his decision netted him over $100,000. Mayer partnered with Richard A. Rowland in 1916 to create Metro Pictures Corporation, a talent booking agency, in New York City.

In late 1922, Mayer was introduced to Irving Thalberg, then working for Universal Pictures. Mayer was searching for someone to help him manage his small, but dynamic and fast-growing studio. At that first meeting, Thalberg made an immediate positive impression on Mayer, writes biographer Roland Flamini. Later that evening, after Thalberg had left, Mayer told the studio’s attorney, Edwin Loeb, to let Thalberg know that if he wanted to work for Mayer, he would be treated like a son.

Mayer’s big breakthrough was in April 1924 when his company subsequently merged with two others to become Metro-Goldwyn-Mayer (MGM). The 24-year-old Thalberg was made part-owner and accorded the same position as vice president in charge of production.

Jackie Coogan, then 11, marked the studio’s debut using child stars with his role in The Rag Man in 1925. During Hollywood’s golden age, MGM had more child actors than any other studio, including Jackie Cooper, Mickey Rooney, Judy Garland, Freddie Bartholomew, Margaret O’Brien, Elizabeth Taylor, and Roddy McDowall.

Loew died in 1927, and Schenck became president of Loew’s. Mayer and Schenck hated each other intensely; Mayer reportedly referred to his boss, whose name was pronounced “Skenk”, as “Mr. Skunk” in private. Two years later, Schenck agreed to sell Loew’s – and MGM – to William Fox, which angered Mayer. But despite his important role in MGM, Mayer was not a shareholder, and had no standing to challenge the sale. So he instead used his Washington connections to persuade the Justice Department to delay the merger on antitrust grounds. During the summer of 1929, Fox was severely injured in an auto accident. By the time he recovered, the stock market crash had wiped out his fortune, destroying any chance of the deal going through even if the Justice Department had lifted its objections. Nonetheless, Schenck believed Mayer had cost him a fortune and never forgave him, causing an already frigid relationship to get even worse.

Active in Republican Party politics, Mayer served as the vice chairman of the California Republican Party in 1931 and 1932, and as its state chairman in 1932 and 1933. As a delegate to the 1928 Republican National Convention in Kansas City, Mayer supported Secretary of Commerce Herbert Hoover of California. Mayer became friends with California Governor James Rolph, Jr., Oakland Tribune publisher Joseph R. Knowland, and Marshall Hale. Joseph M. Schenck was an alternate delegate at the convention. Mayer was a delegate to the 1932 Republican National Convention with fellow Californians Knowland, Rolph, and Earl Warren. Mayer endorsed President Herbert Hoover’s failed reelection bid. .

Although they initially got along well, their relationship frayed over philosophical differences. Thalberg preferred literary works over the crowd-pleasers Mayer wanted. He ousted Thalberg as production chief in 1932, while Thalberg was recovering from a heart attack, and replaced him with producer David O. Selznick.

With regard to any technical issues with productions, Mayer left the details and solutions to MGM’s engineers. He, though, like other top film executives and Hollywood stars in the 1920s and early 1930s, was often too quick to dismiss news of inventions and major innovations on the horizon that might profoundly change the movie industry or possibly challenge in the future the growing dominance of films in the realm of American entertainment. Beyond the well-entrenched aspect of sound by 1932, other technologies being discussed at that time in newspapers and on studio lots included color features, widescreen formatting, and even early television. In August 1932, after an “exclusive” interview with Mayer in New York, The Film Daily reported the movie mogul’s assertions that the noted developments would never impact motion pictures in substantial, meaningful ways:

But MGM received a serious blow when Thalberg died suddenly on September 14, 1936, at age 37. His death came as a shock to Mayer and everyone at MGM and the other studios. Mayer issued statements to the press, calling Thalberg “the finest friend a man could ever have … the guiding inspiration behind the artistic progress on the screen.” His funeral was a major news event in Los Angeles. All the studios observed five minutes of silence, while MGM closed its studio for the entire day.

While MGM’s films during the 1920s and 1930s were often notable for having adult themes and strong female stars, such as Greta Garbo, after Thalberg’s early death in 1936, Mayer promoted a change in emphasis to more male leads, family themes, and child stars. And unusual for a movie mogul, he took moral positions in his movies, especially when it came to portraying family values—as in the Andy Hardy series. One of Mayer’s proudest moments came when Mickey Rooney, who starred as Andy Hardy, was given a special award by the Academy in 1942 for “furthering the American way of life.”

Unlike Charlie Chaplin, who produced The Great Dictator, the other, much larger Hollywood studios lacked the freedom to make such independent films. Mayer understood that the Germans could ban or boycott Hollywood films throughout much of Europe, with serious economic implications, since 30 to 40 percent of Hollywood’s income came from Europe’s audiences. Nevertheless, MGM produced Three Comrades in 1938, despite movie censor Joseph Breen warning Mayer that the film was “a serious indictment of the German nation and people and is certain to be violently resented by the present government in that country.”

After the war erupted in Europe in September 1939, Mayer authorized the production of two anti-Nazi films, The Mortal Storm and Escape. At the same time, Warner Brothers produced Confessions of a Nazi Spy. The German government informed the studios that “those films would be remembered by Germany when — not if — they won the war”, writes Eyman. Warners had to post guards to protect the family of actor Edward G. Robinson, and the Germans threatened Mayer with a boycott of all MGM films.

From September 1939 until January 1940, all films that could be considered anti-Nazi were banned by the Hays Office. The U.S. ambassador to England, Joseph Kennedy, told the studios to stop making pro-British and anti-German films. Kennedy felt that “British defeat was imminent and there was no point in America holding out alone: ‘With England licked, the party’s over,’ said Kennedy.”

The following year, 1943, saw the release of another Oscar-winning film, this one aimed at supporting the home front, entitled The Human Comedy. It was Mayer’s personal favorite and the favorite of its director, Clarence Brown. Mayer also assisted the U.S. government by producing a number of short films related to the war, and helped produce pro-American films such as Joe Smith, American, in 1942.

While Mayer seldom discussed his early life, his partiality towards Canada would sometimes be revealed, especially after Canada and the United States entered World War II. On one occasion in 1943, Mary Pickford called to tell him she met a movie-struck Royal Canadian Air Force pilot from New Brunswick, where Mayer grew up. Mayer asked her to have him drop by the studio. The pilot, Charles Foster, recalled his visit: “Mary’s driver took me through the gates, and I saw this little man come running down the steps of the Thalberg Building. I thought, ‘Oh, he’s sent a man to greet me.’ And I got out of the car, and this man threw his arms around me and said, ‘Welcome to my studio.’ “

The post-war years saw a gradual decline in profits for MGM and the other studios. The number of high-grossing films in 1947 dwindled to six, compared to twenty-two a year earlier. MGM had to let go many of its top producers and other executives. Mayer was pressured to tighten expenses by the studio’s parent company, although Mayer’s reputation as a “big-picture man” would make that difficult. They began looking for someone, another Thalberg, to redo the studio system.

Mayer owned or bred a number of successful thoroughbred racehorses at his ranch in Perris, California, near Los Angeles. It was considered one of the finest racing stables in the United States and raised the standards of the California racing business. Among his horses were Your Host, sire of Kelso; the 1945 U.S. Horse of the Year, Busher; and the 1959 Preakness Stakes winner, Royal Orbit. Eventually Mayer sold off the stable, partly to finance his divorce in 1947. His 248 horses brought more than $4.4 million. In 1976, Thoroughbred of California magazine named him “California Breeder of the Century”.

In the interim, Mayer kept making “big pictures.” When RKO turned down financing of Frank Capra’s State of the Union in 1948 because of its expensive budget, Mayer took on the project. He filled the cast with MGM stars including Katharine Hepburn, Spencer Tracy, Van Johnson, Adolphe Menjou and Angela Lansbury, but the film only broke even. Nicholas Schenck called Mayer and insisted that he “cut, cut”, recalls director George Sidney. Mayer replied, “A studio isn’t salami, Nick.” “L.B. would ask only one question: ‘Can you make it better?’ It was all he cared about”, said Sidney.

As pressure built to find a new Thalberg-style manager to handle production, Dore Schary was brought in from RKO, and began work on July 14, 1948, as vice president in charge of production, working under Mayer’s direction.

By mutual consent with Loew’s, Mayer resigned from MGM in August 1951. On his final day, as he walked down a red carpet laid out in front of the Thalberg Building, executives, actors and staff lined the path and applauded him for his contributions. “He was so respected,” said June Caldwell, Eddie Mannix’s secretary. Many assumed that his leaving meant the end of an era. Actor Turhan Bey said, “In every meaningful way, it was the end of Hollywood.”

In 1951 he was given an honorary Oscar for heading MGM for over 25 years. At the event, screenwriter Charles Brackett presented the award and thanked him for guiding MGM’s “production policy with foresight, aggressiveness and with a real desire for taste and quality.” Mayer was also thanked for founding and developing new personalities and for bringing the Hollywood “star system into full flower.”

Mayer, for a period after he left MGM, tried to finance and assemble a new group of film stars and directors to produce his own films as an independent. He told the press that his films would carry on in the tradition of MGM’s previous style of film subjects. In 1952 he became chairman of the board and the single largest shareholder in Cinerama, and had hoped to produce a property he owned, Paint Your Wagon, in the widescreen process, but without success. He left Cinerama in 1954 when the company was sold.

Mayer died of leukemia on October 29, 1957. He was buried in the Home of Peace Cemetery in East Los Angeles, California. His sister, Ida Mayer Cummings, and brothers Jerry and Rubin are also buried there.

Mayer never wrote or directed movies, and never pretended to tell writers what to write or art directors what to design. But he understood movies and their audience. According to Eyman, “Mayer’s view of America became America’s view of itself.” Because of the stars, the stories, the glamour, the music, and the way they were presented, audiences the world over would often applaud the moment they saw the MGM lion. Mayer was the constant at MGM who set the tone. At Mayer’s funeral in 1957, Spencer Tracy expressed Mayer’s ambitions:

William Saroyan wrote a short story about L. B. Mayer in his 1971 book, Letters from 74 rue Taitbout or Don’t Go But If You Must Say Hello To Everybody.