In January 1877, the Territorial Library had 1,900 legal books and 300 non-legal volumes, which could be checked out by the public during regular hours.

It was not until July 6, 1886, after money was raised for the needed items, that the Tucson Public Library first opened its doors.

The city council passed Resolution #20 in 1899, which provided land that was part of the Military Plaza for the site and set up the Library Fund.

As of July 1, 2006, the library system is wholly funded and governed by the Pima County and its Board of Supervisors.

101 Space at Joel D. Valdez Main Library also provides a safe place for teens to hang out, create, and try out new technologies like 3D printers and green screens.

In 2012, the Tucson Unit of the National Writers Union (NWU) publicly raised objections to the library's collection development policy.

In its reply to the piece, the PCPL stated that its collection development policy is geared toward "making room on the shelves for high-demand and popular books and materials in other formats" and pointed out that library circulation had increased from 6.2 million items in 2006 to more than 7.5 million items in 2010.

The first of these highlighted how the library was forced to supplement its standard security service with off-duty officers from the Tucson Police Department.

This was done to provide additional security at three of the library branches in which an unusually high number of incidents, ranging from fights to domestic disputes, had taken place.

[9] The second KVOA News report focused on how "hundreds of thousands of dollars in inventory is going missing from the libraries and nobody seems to know why," and how the library, though spending 750,000 dollars a year on security, is not particularly focused on securing or protecting the books, DVDs and CDs in its collection.