The full-block site was previously occupied, in its southeast quadrant, by the Rosenblatt Building, which was built in 1889 and demolished in early 1967.

[11] In 1986, after Mittleman's death, the building was owned by his estate, but the "long-term master lease" was planned to be transferred from the Bank of California to a partnership of Melvin Mark Properties and Douglas Goodman in January 1987.

[12] The bank continued to be the building's primary tenant, leasing 56,000 square feet (5,200 m2) of the overall 197,000 sq ft (18,300 m2) of space at that time.

[1] The tower was designed by the firm of Anshen and Allen of San Francisco in the International Style, with a strong presence on Broadway.

A distinctive feature of the Union Bank Tower are its exposed service cores, on the building's south and west sides, which are clad in light gray slate with a greenish tint.