LaGuardia was born in The Bronx and grew up in New York City and was educated at the New York University. The family moved to Trieste after his father was discharged from his bandmaster position in the U.S. Army in 1898. La Guardia served in the U.S. consulate at Fiume (1904–1906). Fiorello returned to the U.S. to continue his education, and during this time he worked as a translator at Ellis Island (1907–1910).
He became the deputy attorney general of New York in 1914. In 1916 he was elected to the New York State House of Representatives, where he developed a reputation as a fiery and devoted reformer. In Congress, LaGuardia represented then-Italian East Harlem. Extending his record as a reformer, LaGuardia sponsored labor legislation and railed against immigration quotas. He was overwhelming defeated by incumbent James J. Walker in the 1929 mayoral election.
LaGuardia was elected mayor of New York City on an anti-corruption "fusion" ticket during the Great Depression. LaGuardia was the City's first Italian American mayor, but LaGuardia was far from being a typical Italian New Yorker. He was Republican, Episcopalian, had grown up in Arizona, and had a Jewish mother.
LaGuardia had run for mayor against, and was crushed by, Walker in the 1925 election, having unsuccessfully campaigned on a platform of anticorruption by pointing a morally accusing finger at the flamboyant administration during the good times, when nobody cared.
LaGuardia was determined to destroy the pinball "scourge of the city's children" by declaring war on what had become a national obsession, and to him the symbol of all that had gone wrong in America.
LaGuardia fought back, broadening his fingerprint policy so that only those musicians who had secured a city-issued cabaret license could play in any of the boroughs-which was said to be only slightly less difficult to acquire than a gun permit for any performer who'd ever gotten so much as a speeding ticket.