During the 20's Women Right's activist Ella Lillian Wall Van Leer would help create and manage various Art and Architecture departments.

Crescenta Valley High School opened in September 1960, taking a sizable portion of Glendale's students.

On July 1, 2005, Katherine Fundukian replaced LeRoy Sherman and Lou Stewart as co-principals, as part of a School District decision to move Glendale High School back to a "traditional" one-principal system from the two-principal system that had been in place.

In 2006, eight students from Glendale High School represented the United States at the Junior G8 summit in Saint Petersburg, Russiawhere they discussed world issues and met with the leaders of the G8 nations.

Glendale High's mathematics department received the highest average AP scores in the United States in 2012.

The Glendale High School Junior Varsity and Varsity dance/drill team competes annually at the United Spirit Association Nationals competition and starting in the 2018 Season now competes annually at the West Coast Elite Dance Nationals competition.

"[6] That team was directed by coach Normal C. Hayhurst, with University of Southern California student Vic Francy serving as one of the assistants.

Students from each class (Grades 9, 10, 11, and 12) are judged on: The tradition was started in 1910, at a time of heightened interest in public speaking in Southern California.

The award is given to the graduating senior who best exemplifies Navolanic's leadership traits, scholarship skills and athletic prowess, as decided by a council of electors representing all student organizations and sports teams on campus.

The scholarship money is made possible by a financial endowment, as well as generous donations from students, teachers, alumni and the community.