On September 4, 1929 ceremonies took place for Herbert Hoover Senior High School. Hoover’s construction was completed on July 2, 1930. The school opened its doors to 960 students on September 2, 1930. An excerpt from the first issue of the Cardinal sets the scene: "The three story administration building in buff colored stucco is solid and durable, yet it is built along peaceful lines. In many ways it resembles Spanish architecture. From the wide halls one enters well lighted classrooms. The large windows, extra high ceiling, and cool breeze make the rooms pleasant for study. The wood work, which is colored a soft green, is pleasing and restful to the eye. The new type of student desks, which are made of dark wood, are comfortable and practical. The library is the pride of the school. The light flickers through amber tinted windows into a picturesque room with a delightful balcony. The gymnasiums are so attractively arranged that they make exercise a joy. The new auditorium, though not completed, is sure to reveal beauty and comfort. The fact that the drinking fountains enable two students to drink at the same time is very agreeable to everyone."

The staff of Hoover was made up primarily of teachers from Wilson Middle School and Point Loma High School. The first principal was Floyd A. Johnson, who urged students to "let us dream for our school as we dream for ourselves." The first football practice drew 88 students, nearly 20% of the male population at Hoover. The Hoover President's first game was played against Grossmont High, with Hoover emerging victorious, 7-6.

Hoover pioneered the commissioner plan of student government in its inaugural year, the first high school in San Diego to adopt this democratic form of governance. On October 6, 1930, the "Hoover Cardinal" was officially chosen as the name of the school paper in a student body vote. Cardinal and white were adopted as the school colors at the same time, after the colors of Stanford University, the alma mater of Herbert Hoover. The nickname of the Cardinals seems to have evolved from the colors, as shortly after this vote the "Presidents" ceased to be known by that name.

As Hoover's first basketball team began league play, the Depression deepened, with over four million people unemployed by the end of the year. February saw the release of Charley Chaplin's film "City Lights." As Valentine's Day approached, Hoover students purchased 1 pound of chocolate for their sweethearts at the Hoover Drug Store, located directly across the street from campus. On April 4 Herbert Hoover High School was formally dedicated before 1,500 attendees. President Hoover's message to the school was read; this letter and an autographed picture were presented for hanging in the library. To cap off the first year of athletics, the Hoover baseball 9 won the San Diego City Championship by defeating Point Loma High in a 10 inning game played before over 1800 fans.

As the 1931-32 academic year commenced, Hoover instituted the Hoover Community Center, located at the school, offering night classes; this tradition continues today with the High School Diploma Program. October 21 saw the first league pigskin victory of the year, a 50-0 romp over neighboring La Jolla High. Hoover's basketball team won its first City League Championship in February with a win over the Army and Navy Academy; they would go on to capture the Southern California title one month later.

Hoover's first graduating class had their commencement exercises on Wednesday, June 15 in the Senior Patio, 165 seniors participated. The first Senior Ball was held at the San Diego Club on Friday, June 17. In 1932, the United States was host to its first Winter Olympic games as the Depression grew deeper and deeper; the number of unemployed reached 13,000,000. By 1933 some 2,000,000 teachers were unemployed; it was estimated that over 2 and a quarter million children were not attending school.

By this time many Hoover traditions were well established. Football games were a community event; the end of the season match-up with San Diego High drew thousands. Due to the size of the San Diego area, football games away involved travel to Santa Ana, Santa Barbara and later even El Centro and Yuma. In November Hoover's football team traveled to Los Angeles to beat Loyola for the Southern California championship. Clubs of all interest areas were well represented at Hoover: California Scholarship Federation, Debate Club, Hi-Y, Girl Reserves, Boy's and Girl's Glee Clubs, Orchestra, Drama Club, Quill and Scroll, Ballyhoo Club and others.

In the fall of 1935 lights were installed on the football field as well as bleachers with a capacity of 5,000. The lights were financed in part by each faculty member loaning the ASB $10.00 from their first month's salary. By this time Hoover had become a definite force in San Diego Intersectional Athletics; the 1935 baseball and football teams each won all but three of their games while the basketball B team became champions of Southern California for the third time. Hoover in the thirties also had an orchestra, which performed both for the school and the community in a number of concerts. This year also marked the first time the senior class had gone to the mountains for Senior Ditch Day; the site was Pine Valley on May 15. The June class was 241 strong.

Hoover students at the time did not live in a vacuum as the first decade of its existence drew to a close. A Cardinal editorial published on June 7, 1940 states: "If . . . . . the United States remains out the war the road ahead appears bronze and bright. We wouldn't, as seems inevitable, graduate just in time to trade our diplomas for guns." Little did the writer realize that one year later to the day, Hoover students would be doing just that.