Mencken was born in Baltimore, Maryland, the son of a cigar factory owner. He became a reporter for the Baltimore Morning Herald in 1899, and moved to the Baltimore Sun` in 1906. In 1908 he also began writing as a literary critic for the magazine The Smart Set. He founded his own influential magazine, The American Mercury in January of 1924, which soon had a national circulation. In his capacity as editor and "man of ideas" Mencken became close friends with the leading literary figures of his time, including Theodore Dreiser, F. Scott Fitzgerald, and Alfred Knopf.
Mencken was an outspoken defender of freedom of conscience and civil rights, an opponent of persecution and of injustice and of the puritanism and self-righteousness that masks the oppressive impulse. As a nationally syndicated columnist and author of numerous books he played an important role in ending America's preoccupation with fundamentalist Christianity, and opened the way for a secularist revival.
Mencken's views are usually regarded as libertarian by most commentators, but Mencken's writing also had a strong elitist strain and even a racist attitude is present:
Mencken suffered a cerebral thrombosis in 1948, from which he never fully recovered. Ironically, and sadly, the damage to his brain left him fully conscious and aware but unable to read or write. In his later years he enjoyed listening to classical music and talking with friends, but he sometimes referred to himself in the past tense as if already dead. He died in 1956 and was interred in the Loudon Park Cemetery in Baltimore, Maryland. His epitaph reads: