Walter Whitman (May 31, 1819 – March 26, 1892) was an American poet, essayist, journalist, and humanist. He was a part of the transition between Transcendentalism and Realism, incorporating both views in his works. Whitman is among the most influential poets in the American canon, often called the "father of free verse". His work is also very controversial, particularly his poetry collection Leaves of Grass, which has been described as obscene for its overt sexuality.

Born on Long Island in 1819, Whitman worked as a journalist, a teacher, a government clerk, and a volunteer nurse during the American Civil War in addition to publishing his poetry. Early in his career, he also produced a temperance novel, Franklin Evans (1842). Whitman's major work, Leaves of Grass, was first published in 1855 with his own money. The work was an attempt at reaching out to the common man with an American epic. He continued expanding and revising it until his death in 1892. After a stroke towards the end of his life, he moved to Camden, New Jersey while his health further declined. He died at age 72 and his funeral became a public spectacle with live music, speeches, and refreshments.

Whitman's sexuality is often discussed alongside his poetry. Though he is usually labeled as either homosexual or bisexual, it is unclear if Whitman ever had a sexual relationship with another man. He did have several close friendships with men, including Peter Doyle, but the extent of those relationships is debated. Whitman was also concerned with politics throughout his life. He supported the Wilmot Proviso but did not believe in the abolitionist movement.