Born in Stockholm to Sigrid Elisabeth Lindforss and Gösta Oldenburg, a diplomat attaché to the Swedish Consulate in New York.
The Oldenburgs move to Oslo and remain there until 1936.
They settle in Chicago, where Gösta served first as consul and later as consul general until his retirement in 1959.
Claes Oldenburg graduates from the Latin School of Chicago and majors in English literature and art at Yale University.
He takes night courses, and day courses later, at the Art Institute of Chicago, while working first as apprentice reporter for the City News Bureau.
First public exhibition in a group show at the Club St. Elmo, Chicago.
Leaves the Art Institute of Chicago; exhibits his drawings at 1020 Art Center. To support himself he works in the music department of a bookstore and as illustrator for Chicago magazine