Charles John Olson (27 December 1910 – 10 January 1970) was a second generation modernist American poet who was a link between earlier modernist figures such as Ezra Pound and William Carlos Williams and the third generation modernist New American poets. The latter includes the New York School, the Black Mountain School, and some of the artists and poets associated with the Beat generation and the San Francisco Renaissance.

Today, Olson remains a central figure of the Black Mountain Poetry school and is generally considered a key figure in moving American poetry from modernism to postmodernism. In these endeavors, Olson described himself not so much as a poet or a historian but as "an archeologist of morning."

Olson was born to Karl Joseph and Mary (Hines) Olson and grew up in Worcester, Massachusetts, where his father worked as a mail carrier. He spent summers in Gloucester, Massachusetts, which was to become his adopted hometown and the focus of his writing. At high school he was a champion orator, winning a tour of Europe (including a meeting with William Butler Yeats) as a prize. He studied English literature at Wesleyan University, where he graduated Phi Beta Kappa in 1932 before earning an M.A. in the discipline (with a thesis on the oeuvre of Herman Melville) in 1933. After completing his M.A., Olson continued his Melville research at Wesleyan during the 1933–1934 academic year with partial fellowship support. For two years thereafter, he taught English as an instructor at Clark University in Worcester, Massachusetts.

Olson entered Harvard University as a doctoral student in English in 1936. He eventually joined the newly-formed doctoral program in American Civilization as one of its first three candidates. Throughout his studies, he worked at Winthrop House and Radcliffe College as an instructor and tutor in English. Although he completed his coursework by the spring of 1939, he failed to finish his dissertation and take the degree. He then received the first of two Guggenheim Fellowships for his studies of Melville; a monograph derived from his master's thesis and subsequent research, Call Me Ishmael, was published in 1947. His first poems were written in 1940.

In 1941, Olson moved to New York City's Greenwich Village and began living with Constance "Connie" Wilcock in a common-law marriage; they had one child, Katherine. During this period, he was employed as the publicity director for the American Civil Liberties Union (May 1941 – July 1941) and as chief of the Common Council for American Unity's Foreign Language Information Service (November 1941 – September 1942). At that point, they moved to Washington, D.C., where he worked in the Foreign Language Division of the Office of War Information, eventually rising to associate chief under Alan Cranston.

Upset about the increasing censorship of his news releases, Olson went to work for the Democratic National Committee as director of the Foreign Nationalities Division in May 1944. In this capacity, he participated in Franklin Roosevelt's 1944 presidential campaign, organizing "Everyone for Roosevelt", a large campaign rally at New York's Madison Square Garden. Following Roosevelt's re-election to an unprecedented fourth term, he wintered in Key West, Florida. In January 1945, he was offered his choice of two positions (including Assistant Secretary of the Treasury and the Cabinet-rank Postmaster General) in the Roosevelt administration. Increasingly disenchanted with politics, he turned down both posts.

The death of Roosevelt and concomitant ascendancy of Harry Truman in April 1945 inspired Olson to dedicate himself to a literary career. From 1946 to 1948, Olson visited Ezra Pound at St. Elizabeths Hospital, drawn to the poet and his work though repelled by some of his political ideas.

In September 1948, Olson became a visiting professor at Black Mountain College in North Carolina, replacing longtime friend Edward Dahlberg for the academic year. There, he would work and study beside such artists as the composer John Cage and the poet Robert Creeley. He subsequently joined the permanent faculty at the invitation of the student body in 1951 and became Rector shortly thereafter. While at Black Mountain, he had a second child, Charles Peter Olson, with one of his students, Betty Kaiser. Kaiser became Olson's second common-law wife following his separation from Wilcock in 1956.