Built in 1966,[3] the thirty story high-rise was designed by Skidmore, Owings and Merrill,[4] and for its first decades in existence it was used almost exclusively by law firms.

[3] It sold in 2013 from Hines Real Estate Investment Trust to GI Partners for $437.5 million, the highest price ever paid for an office building in downtown Los Angeles.

[3][4] The high-rise was designed by Skidmore, Owings and Merrill[4] and built by Del E. Webb Construction[9] to be a standard office building[2] with thirty floors[2] and 664,000 square feet (61,700 m2) of space.

[5] "Traditional corporate tenants" began moving out in the early 1990s,[2] and the building instead became popular with telecommunications companies, in part because the AT&T Switching Center was only two blocks away.

Long distance carrier MCI thus mounted its own microwave station on the roof of One Wilshire, at the time one of the tallest buildings with good lines of sight in downtown.

[5] CRG West of the Carlyle Group managed the property as of 2007, with 23 of the building's floors designed to hold communications infrastructure as compared to offices.

[3] As a primary terminus for fiber-optic cable routes between Asia and North America,[3] One Wilshire was also the most important telecommunications hub in the western United States.

[3] Hines Real Estate Investment Trust sold the building to GI Partners in July 2013, for a total of $437.5 million in US currency.

[2] Its largest tenant continues to be CoreSite Realty Corporation,[2][5][18] a data center provider which established an office in One Wilshire upon its founding in 2001.