The building was opened in 1933 by the U.S. government as a U.S. Public Health Service Marine Hospital,[3] replacing a facility in Port Townsend.

The hospital originally served veterans, merchant seamen, the U.S. Coast Guard, the U.S. Lighthouse Service, and poor and indigent people defined as "federal compensation cases".

Lease revenues are to advance the PHPDA's mission of providing health care services to low-income uninsured and under-insured persons in King County.

[7] As the medical organization struggled financially, attempts to lease at least 155,000 sq ft (14,400 m2) of the building failed over the course of several years.

With medical facilities continuing to occupy the bottom two floors of the building in 1998, Amazon.com signed a sublease for $1.5 million a year through 2010.

The building suffered substantial damage during the 2001 Nisqually earthquake as the structure's upper floor twisted in a corkscrew fashion.

[8] During repairs, efforts were made to reuse the brick and terracotta, and the same colors and style were sourced when replacement was needed.

In 2010, Amazon.com ended its sub-lease with WRC.Com Tower LLC and began the move of its headquarters to a new campus in the city's South Lake Union neighborhood.

[11] Washington State House Speaker Frank Chopp spearheaded a plan to use government funding to move community college health programs into the building.

[12] In August 2013, the PHPDA announced a 30-year lease with the Washington State Department of Commerce for 13 stories of Pacific Tower.

[14][15] In October 2022, construction began on a seven-story addition to the Pacific Tower that is planned to include 270 units of affordable housing.

The addition includes two buildings on the north side of the tower with an early childhood education center operated by El Centro de la Raza and offices for an unspecified non-profit tenant.

[16] The project is managed by the Pacific Hospital Preservation & Development Authority and financed with loans and grants from local governments and private contributors, including Amazon.

[17] Architectural firm Bebb and Gould, assisted by the John Graham Company, designed the original structure.