The ballpark was located in the largely undeveloped Mission Valley region of San Diego. The location was on Friars Road at State Route 395 (now State Route 163), in the northeast corner of what is now the Fashion Valley Mall.
Westgate was built to replace the deteriorating Lane Field, where the minor-league Padres had played since 1936. Constructed for $1 million in private funds by Padres owner C. Arnholt Smith, Westgate was a modern stadium with a capacity of 8,268 fans, with an eye to be expanded to major league size (up to 40,000) if necessary. In 1958 when it opened, "Not even Yankee Stadium or Boston's Fenway Park can surpass the comforts and conveniences of the Padres' new home. ... This is a real ballpark, built for the game of baseball, a ballpark in which the city of San Diego can take great pride." It was named for the Westgate-California Tuna Packing Corporation.
The first Padres games played in Westgate were on April 28, 1958, a day-night doubleheader versus the Phoenix Giants. The afternoon game attracted 4,619 fans, while the nightcap attracted 7,129 fans.
However, the American Football League's San Diego Chargers were demanding a new stadium to replace Balboa Stadium, a structure dating from about 1915. With major league baseball soon to arrive, the city decided to build a single, multi-purpose stadium for both baseball and football. The new facility was initially called San Diego Stadium. In 1980 it was renamed San Diego Jack Murphy Stadium to honor local sportswriter Jack Murphy, who had recently died. Murphy had been instrumental in building support for the stadium and bringing both the NFL and MLB to San Diego. In 1997 the facility was renamed Qualcomm Stadium after the prominent San Diego-based company purchased the naming rights. The Padres moved to the new downtown Petco Park baseball field in 2004.
The announcement spelled the end of dreams of expansion for Westgate. The minor league Padres played the 1968 season in the cavernous (by PCL standards) new stadium, knowing they were a lame duck, with the major league San Diego Padres set to begin play the next year. Plans for Fashion Valley Mall were unveiled in December 1967, and Westgate was razed by 1969.
- "Previous Homes of the San Diego Padres". San Diego Union-Tribune. April 4, 2004. Retrieved 11 January 2016.
- Crawford, Richard (April 9, 2009). "Westgate Park a major marvel as home for minor-league Padres". San Diego Union-Tribune. Retrieved 11 January 2016.
- Murphy, Jack (April 22, 1958). San Diego Union. Missing or empty
- Fetzer, Leland (2005). San Diego County Place Names A to Z. San Diego: Sunbelt Publications. p. 154.