Our basic principle is to mature people who continue to have wide and profound compassion for humanity, who serve society, and who have the ability to live powerfully in the spirit of Christianity. Accordingly, our policy is to "limit rules to the minimum." Through human communication based upon trust between students and teachers, students learn to behave and be responsible for their own behavior. The fostering of independence and creativity are also emphasized. Entrance examinations are considered part of a lifelong learning process, instead of competition for entering the next level of educational institution.

As shown by the phrase, "Seigakuin is excellence in English," thorough English education is given throughout junior and senior high school. The overseas study program is one of the most significant programs of our school, which covers not only high school students but also junior high school students. Our school has a high ratio of students going on to further their education, with 95% of the students entering university. The students are divided into respective classes and given lessons appropriate to their universities of preference.