St. Ignatius was founded as a one-room schoolhouse on Market Street by Anthony Maraschi, a Jesuit priest, just after the California Gold Rush in 1855.

In the 1860s, the school built a new site, adjacent to the first, on Market Street in downtown San Francisco.

[5] Though founded as an all-boys school, SI became coeducational in 1989 and is now home to over 1,500 male and female students.

[7] In addition, the crew competed in the Henley Royal Regatta in England, where it won the prestigious Princess Elizabeth Challenge Cup in 2006.

[8] More recently, the varsity men's team placed 4th in the SRAA National Championship under the Boys Junior 8+ category in 2022, and won the event in 2024.

[10] The SI women's lacrosse team has historically seen success as well, winning the WCAL title for five years straight from 1997 to 2001.

They won the inaugural Northern California championship in 2018 and were ranked number 2 nationally to end the season.

[citation needed] St. Ignatius' traditional rival is Sacred Heart Cathedral Preparatory, also located in San Francisco.

[15] SI and SHC compete against each other in football, basketball, baseball, and volleyball for the Bruce-Mahoney Trophy, which is named after naval airman, Bill Bruce '35 of St. Ignatius, and Jerry Mahoney of Sacred Heart Cathedral, both alumni who died in World War II.