The official opening of the school was held October 5th, 1977 with the following people present: Dr. Pat McGeer, Minister of Education, Chief Delbert V. Guerin, Musqueam Indian Reserve, Mr. Smedly, Chairman of the School Board, Susan Howatt, Student Council Prime Minister, W. Collins and Brockington, architects, Superindendent of Schools, G. Moulds, and Principal A.E. Coleman.

The school name was determined by a contest where students and members of the community sent in their suggestions. The Board of School Trustees chose the name 'Seaquam' which means 'the sun' or 'sunshine' in the Musqueam language.

Seaquam Secondary School opened on September 6, 1977. The original teaching staff of thirty-seven increased in September, 1977 to forty-one because one hundred more students enrolled than expected. In the initial year, the school enrolled six hundred thirty-three students in grades 7 to 11. Then grade 12 was added, and grade 7 was dropped to create our present 8-12 configuration. It is interesting to note that some of the teaching staff remain from the original group. Since September 1977, school enrollment has increased to over thirteen hundred students, with 70 teaching staff.

Seaquam Secondary has developed into a succesful and comprehensive school with a reputation for having strong programs in the areas of academics, athletics, student leadership, vocational preparation, and the visual and performing arts.

The commitment to scholastic excellence by teachers and students at the school is illustrated by student success. Seaquam Secondary graduates have earned places in post-secondary institutions across Canada and the United States. Many of those same students have been awarded prestigous scholarships and bursaries in recognition of those academic achievements.

Mr. A. E. Coleman was the first Principal until 1991 when he was replaced by Mr. E. Lorenz. 

In September 2011, Seaquam Secondary introduced the International Baccalaureate (IB) Diploma Programme as an alternative to Advanced Placement courses in grades 11 and 12.

The IB Diploma is a prestigious international pre-university qualification and is recognized by universities and governments throughout the world. It has been in existence for over 30 years and is now offered in more than 1,000 schools in 95 countries.