In 1951, poet Frank O'Hara got a job selling postcards at the gift shop of the Museum of Modern Art in New York City—just so he could have access to see the paintings. Only four years later, he returned to the MoMA, but this time as an administrator. His quick ascension speaks to the passion, knowledge, and enthusiasm he had for the New York City art world, a world that was thoroughly infused into his writing. During the 1950s and 1960s, O'Hara befriended and championed the new downtown artists, curated exhibits, wrote monographs and catalog copy, and expressed his various and unusual ideas about the art world in his own poetry.

O'Hara was also the subject of numerous portraits by New York School painters, including Nell Blaine, Grace Hartigan, Larry Rivers, and Jane Freilicher, who suggested that O'Hara appeared in so many paintings because he was always hanging around artist's studios. O'Hara wanted to be as involved in the artistic process as possible, whether it meant stretching canvases or posing as a model. He built close associations with Willem de Kooning and Jackson Pollock, who were just beginning to be known as Abstract Expressionists. He also befriended up-and-coming painters such as Richard Diebenkorn and Cy Twombly.

When O'Hara returned to work at the MoMA as a special assistant in 1955, he had developed his friendships with several important painters, and he had become a notable and prolific reviewer for magazines such as ARTnews. He was invited to take on more responsibility, including selecting paintings for several important exhibitions, including The New American Painting and the Bienal in Sao Paulo, Brazil, which included a now-famous selection of Pollock paintings. He was a particularly great defender of Pollock's later work, which many critics initially dismissed. Between 1955 and 1966, his curatorial work for the museum was wide-ranging and critically praised; his qualifications were his excellent eye for art and a knowledge of various painting traditions, though he lacked the formal schooling usually necessary for museum work.

However, poetry and painting were not held sacred above other art forms. "After all," he wrote, "only Whitman and Crane and Williams, of the American poets, are better than the movies." O'Hara enjoyed the arts freely and unpretentiously, taking in a ballet as frequently and casually as one might see a movie. In "Having a Coke with You" he writes:

               I look
at you and I would rather look at you than all
    the portraits in the world
except possibly for the Polish Rider occasionally
   and anyway it's in the Frick
which thank heavens you haven't gone to yet so
   we can go together for the first time
and the fact that you move so beautifully more
   or less takes care of Futurism
just as at home I never think of the Nude
   Descending a Staircase

His art criticism was as free as his poetry; while never completely straying from precise critical language, he allowed himself some poetic diversions when the subject called for it. For example, in a review of a Twombly exhibition for ARTnews, he wrote, "Though they are all white with black and grey scoring, the range is far from a whisper, and this new development makes the painting itself the form. A bird seems to have passed through the impasto with cream-colored screams and bitter clawmarks." Of painter John Ferren, he wrote, "some of the pictures had a wild natural humor like a vase of flowers knocked over."

In his poetry, he drew upon the world of painting and sculpture, incorporating contemporary artists and their works by name. He was free to move deeper into poetic language and thought than he had in his criticism, while maintaining the ease, spontaneity, and naturalness characteristic of his work. The Frank O'Hara poem "Why I Am Not a Painter" begins:

I am not a painter, I am a poet.
Why? I think I would rather be
a painter, but I am not. Well,

for instance, Mike Goldberg
is starting a painting. I drop in
"Sit down and have a drink" he
says. I drink; we drink. I look
up. "You have SARDINES in it."

He goes on to sketch the evolution of a painting where the word SARDINES is removed because it's "too much," but becomes the title of the painting. The poetic equivalent is the poem he is writing where he writes pages and pages "of how terrible orange is/ and life" without ever mentioning the color, entitling the poem "Oranges." This is one of the reasons critic and poet Marjorie Perloff called O'Hara "a Poet among Painters": while denying in this poem that he knew anything about visual art, or had any understanding of the process, he shows elegantly and easily the relationship between twin artistic processes, elevating his writing about art to the level of the art he was writing about.