The Pac-12 is operating as a two-team conference through the 2025–26 academic year, sponsoring five sports—baseball, football, track and field, women's gymnastics, and wrestling.

[15] An official of Stanford University also attended the meeting but declined to join right away because, unlike the other schools, it was not going to sponsor a football team in the coming year and it was not willing to prohibit freshmen from competing in sports.

Ten months earlier in August 1958, these four schools agreed to form a new conference that would take effect the following summer.

[16][17] When the four schools and Stanford began discussions for a new conference in 1959, retired admiral Thomas J. Hamilton interceded and suggested the schools consider creating a national "power conference" (Hamilton had been a key player, head coach, and athletic director at Navy, and was the current athletic director at Pittsburgh).

[22] On July 1, 1959, the new Athletic Association of Western Universities was launched, with California, UCLA, USC, and Washington as the four charter members.

[43] Before the addition of Colorado and Utah in 2011, only the Ivy League had maintained its membership for a longer time than the Pac-10 among Division I conferences.

Commissioner Larry Scott said on February 9, 2010, that the window for expansion was open for the next year as the conference began negotiations for a new television deal.

[45] On June 10, 2010, the University of Colorado Boulder accepted an invitation to join the Pac-10 Conference, effective starting with the 2012–2013 academic year.

[50] The Pac-12 Network and meeting space for headquarters employees are now located at Bishop Ranch in San Ramon, an East Bay suburb.

[51] On August 24, 2021, the Pac-12, ACC, and Big Ten announced the formation of a "historic alliance" that would bring their member institutions "together on a collaborative approach surrounding the future evolution of college athletics and scheduling.

"[52] The formation of this alliance between three of the Power Five conferences was in response to Oklahoma and Texas announcing plans to leave the Big 12 and join the SEC.

[53] Despite the alliance, on June 30, 2022, UCLA and USC announced their departure for the Big Ten Conference beginning in the 2024–25 academic year.

[56] Reports began circulating that Commissioner Kliavkoff had been to the San Diego State University and SMU campuses for tours.

[57] San Diego State sent the Mountain West Conference a letter notifying it of the school's impending departure.

Without an incoming offer before a June 30, 2023, deadline, San Diego State had to rescind its notice of intention to leave the Mountain West.

Kliavkoff came back with a deal from the Apple TV+ streaming service that paid member institutions in the low-to-mid-$20 million range, albeit with escalators for meeting subscriber quotas.

On August 4, 2023, Oregon and Washington announced they would be following UCLA and USC to the Big Ten conference for the 2024 season.

[65] The West Coast Conference (WCC) has invited both schools to join as affiliate members for basketball and most other non-football sports.

[74] On November 14, 2023, Judge Gary Libey of the Whitman County, Washington, Superior Court ruled in favor of the two schools.

Total expenses includes coach and staff salaries, scholarships, buildings and grounds, maintenance, utilities and rental fees, recruiting, team travel, equipment and uniforms, conference dues, and insurance.

The following table shows institutional reporting to the United States Department of Education as shown on the DOE Equity in Athletics website for the 2021–22 academic year.

[78] The following table shows revenue specifically from NCAA / Conference Distributions, Media Rights, and Post-Season Football reported by the Knight Commission for the 2021–22 academic year.

[79] Since restarting in 1959 as the AAWU, the Pac-12 has had six commissioners: Commissioners of the forerunner PCC Salaries based on 2022–23 academic year Team titles through the June 10, 2024; individual titles through July 1, 2016[97] These totals do not include football national championships, which the NCAA does not officially award at the FBS level.

Colorado and Utah, who joined in 2011, were historic rivals in the Rocky Mountain region prior to 1962 when they suspended the series.

Previously, the schools did not play one non-rival opponent, resulting in an eight-game conference schedule (four home games and four away).

In 2010, the last season before the arrival of Colorado and Utah, the only other BCS conference that played a round-robin schedule was the Big East.

On October 21, 2010, the Pac-10 announced the creation of divisions and a championship game in football, to be used when Colorado and Utah joined the conference effective July 1, 2011.

As a result, later that same day, the Pac-12 announced that it would eliminate its divisions for the 2022 football season and beyond, with the championship game instead featuring the two Pac-12 teams with the highest winning percentage.

In honor of the 100th anniversary of the establishment of the conference, an All-Century Team was unveiled on December 2, 2015, voted on by a panel of coaches, players, and the media.

Leading the country with the most participants in their respective events are, Colorado in alpine skiing and cycling, Arizona State in archery and badminton, Stanford in baseball, rugby, swimming, tennis and water polo, UCLA in basketball, beach volleyball, gymnastics and softball, USC in athletics and volleyball, and Utah in freestyle skiing.