In 2015, Mark Keppel High theatre students were invited to the Edinburgh Festival Fringe in Scotland where they performed in a rendition of Peter Pan.

The Varsity football team, under coach Eddie Wagner, beat Pasadena High School 19-13 for the 1944 CIF-SS Championship at the Los Angeles Coliseum.

[citation needed] The boys Varsity soccer team of 1979 won the CIF-SS Division III championship by beating Orange County's University High School by the score of 4-2.

Until June 2016, "Idea Magazine" was a student-run, biannual compilation of Mark Keppel students' work in literature and art, advised by AP English teacher Mrs. Patrice Flores.

Mark Keppel High School is designed in the Streamline Moderne architectural style, a variant of the Art Deco, and a product of the Great Depression.

While the Art Deco celebrated the mechanization of the Jazz Age with big, bold, vertical designs, exotic materials, and elaborate decorations, the Streamline Moderne was a more reserved and utilitarian style.

The Streamline Moderne mimicked the fast, dynamic look of machines with sleek, aerodynamic and nautical forms, low horizontal designs, rounded corners, and shiny materials.

The architecture of Mark Keppel High School features rounded corners in and outside the auditorium, on the staircase leading up to the front entrance, and in all the interior stairwells.

Mark Keppel High School features three bas relief murals made by native Southern California artist, Millard Sheets.

The largest mural crowns the entrance to the auditorium and depicts the three main groups that colonized and populated California: the Spanish Conquistadors, the Catholic Missionaries, and American Pioneers.