George Brinton McClellan Harvey was educated at Peacham Academy. At the age of 18, he became a reporter on the Springfield (Massachusetts) Republican and later on the New York World, where he reported on New Jersey politics.
George Brinton McClellan Harvey was appointed by Governor Green of New Jersey as aide-de-camp on his staff, and was reappointed by Governor Abbett. The latter also made him insurance commissioner of New Jersey in 1890. A protégé of publisher Joseph Pulitzer, at the age of twenty-seven he became managing editor of the New York World (1891-1894). It was the flagship newspaper of the Democratic Party, its editorials were widely reprinted by the party press.
Harvey then became associated with Thomas F. Ryan and William C. Whitney leading Democrats who were millionaire promoters of street railways. In 1898 Harvey organized a syndicate which acquired the lines in Havana, Cuba. Having accumulated a great fortune, he purchased prestige magazines, the North American Review in 1899. It had long been the leading national magazine in arts, letters, and politics, but it was soon overshadowed and outsold by the muckraking magazines Harvey disapproved of. In 1901 he also purchased Harper's Weekly, which he edited until 1913. He was president of Harper and Company until 1915. In 1903, Harvey purchased the Metropolitan Magazine.
Harvey was a top advisor to New Jersey governor Woodrow Wilson. In the runup to the start of the 1912 campaign he gave Wilson strong support. But Wilson was moving left and needed to shake off the image that he was under the thumb of Wall Street. Wilson sensed he was jeopardized by Harvey's officiousness and conservatism, while Harvey was alarmed by Wilson's move to the left of the party. Their breakup was the talk of the hour in the national press, and helped Wilson gain support among liberal Democrats.
In 1916 Harvey urged the election of Charles E. Hughes, the Republican candidate for president.
Despite retiring from Harper's Weekly as editor in 1913, he returned in 1918 to use it as a medium for attacking the policies of President Wilson. In 1918, he established The North American Review's War Weekly, later called Harvey's Weekly, which bitterly denounced Wilson's foreign policy.
From 1906 until 1908, he promoted the artificial language Esperanto in the North American Review. In 1908 and 1909 he was president of Esperanto-Asocio de Norda Ameriko (Esperanto Association of North America). He was strongly opposed to the League of Nations in 1919 and 1920 on the ground that it involved the yielding of national sovereignty.
Harvey published a number of works during his life, most notably Women in 1908 and Henry Clay Frick, the Man (1928), a biography of the industrialist, art collector, and philanthropist.
He died on August 20, 1928, at his home in Dublin, New Hampshire.