In his undisciplined and increasingly violent private life, Rivera fathered several children from brief affairs, abandoning all of them. In the early 1920s, he left France and returned to Mexico, where he became interested in left-wing politics. There, he painted his first mural, in which ethnic Mexican subjects were portrayed in a political context.
He would become known for his grand murals depicting the life and history (particularly the popular uprisings) of the Mexican people. Starting in 1921, he began a series of murals in public buildings depicting the Mexican history in an innovative style combining Realism with strong influences of Pre-Columbian MesoAmerican art.
Several marriages and love affairs later he was introduced to Frida Kahlo, a militant Communist. He later went to Moscow, Russia, but was expelled by the authorities because of his involvement in anti-Soviet politics. In 1929, he returned to Mexico, and at age 43 he married the 22-year-old Kahlo.
From 1930 to 1934, he completed a number of frescoes in the United States, mainly of industrial life. In 1933, His Man at the Crossroads mural for the Rockefeller Center in New York City was removed after a furor erupted in the press because it contained a portrait of Lenin. Because of the negative publicity, a further commission to paint a mural for an exhibition at the Chicago World's Fair was canceled. In December 1933, an angry and humiliated Diego Rivera returned to Mexico.