He then studied under master Finnish architect Eero Saarinen at the Cranbrook Academy of Art in Bloomfield Hills, Michigan, receiving his master's degree in architecture and urban design in 1946.
After serving in the U.S. Army from 1946-1947 and working as an architect in the Chicago office of Skidmore, Owings and Merrill from 1947-1951, Obata returned to St. Louis in 1951 to join the firm of Minoru Yamasaki, designer of the World Trade Center towers.