When its new Phillips campus opened in 1904, the school was still predominantly attended by the wealthy children of Chicago's south side mansions, but this soon changed.

Changing demographics resulted from the Great Migration, by which millions of African Americans left the rural South for northern and midwestern industrial cities, including Chicago.

[10] In 1924, the Chicago Board of Education created a junior high school within Phillips, serving seventh and eighth grades.

By 1928, Phillips student population exceeded the capacity of the school building in which the district instituted the use of portable classrooms and the implementation of two half-day shifts.

Shortly before the completion of the new building, Phillips "mysteriously" caught fire on January 28, 1935, making it necessary for the students to move to the new school in February 1935.

During the initial move to the new school, the board decided to only house sophomore, juniors and seniors in the new building due to limited space.

[citation needed] The alumni association and principal Ernestine D. Curry established the Wendell Phillips High School Hall of Fame in 1979.

[13] During the late 1920s, members of the school's winning basketball team were drafted by Abe Saperstein, a Chicago Park District employee,[14] to form the nucleus of a group that later became the Harlem Globetrotters.

[15] Those players included Tommy Brookings, Hillery Brown, George Easter, William "Razor" Frazier, Roosevelt Hudson, Inman "Big Jack" Jackson, Lester Johnson, Byron "Fat" Long, William "Kid" Oliver, Al "Runt" Pullins, Randolph Ramsey, Ted Strong and Walter "Toots" Wright.

Phillips also features a Junior Air Force Reserve Officers Training Corps (JAFROTC) program[19] and a health clinic to serve the needs of its students.

Phillips community and university partners include the University of Chicago, Illinois Institute of Technology, Ada S. McKinley Educational Talent Search, City Year Chicago, Dawson Skills Center, Carnegie Learning, Field Museum, Kaplan, Center for New Horizons, and Project Strive.

[23] Phillips competes in the Chicago Public League (CPL) and is a member of the Illinois High School Association (IHSA).