Originally opened in 1935, the 8,500-seat stadium was expanded in 2006 to its current capacity. In addition, the stadium was renamed Alex G. Spanos Stadium after Alex Spanos, a Cal Poly alum and the owner of the San Diego Chargers, in a ceremony on November 18, 2006. The recognition and subsequent renaming was a result of a $4 million donation to renovate Mustang Stadium by Mr. Spanos. This marked the largest single donation in the school's history.
Proposals to further increase the stadium's capacity to 22,000 are still being considered as of 2013.