It was completed in 1967.
Wow! A virtual tour!!!! (warning: you need JAVA!!!!)
This building (originally called the Alcoa Building) was built as part of one of the earliest projects of the SF redevelopment agency. The project also included construction of the Embarcadero Center and Golden Gateway.
One Maritime Plaza is a black modernist brick. It has X-shaped trusses for seismic safety. They look very similar to the trusses on the John Hancock Building in Chicago. They were both designed by Skidmore, Owings & Merrill. This building was the inspiration for the Hancock. Here's SOM's profile of the building.