It is named after the Armijo family, who purchased one of the original six land grants in Solano County awarded to General Mariano Vallejo.

The school serves about 2600 students in grades 9 to 12 from the central part of Fairfield and Suisun City.

In 1893, a separate wooden building was built for use as the high school.

In 1915, the school moved to a large stone building on Union Avenue in downtown Fairfield that is now used as the Solano County courthouse.

In 2019, the Fairfield-Suisun School District board voted unanimously to replace the "Armijo Indian" mascot.