The present school was opened by the Director General of Education, Dr Robertson, in February 1955. The school was then known as Margaret River Junior High School and had 8 teachers and 357 students from 5 to 15 years of age. The headmaster was Mr F Currell. In February 1962, the primary section became a separate school, leaving Margaret River High School with an enrolment of 264 twelve to fifteen year olds.

A fourth year (Year 11) commercial course was introduced in 1965 to give a year of pre-vocational training for girls. This continued until 1971 when it was discontinued due to lack of numbers. The Margaret River Convent and the Kudardup Primary School closed at the end of 1970. Since then, the High School has collected most of its students from the Primary Schools at Augusta, Karridale, Margaret River and Cowaramup. In 1988 the first students enrolled from the Nyindamurra Family School (now known as Margaret River Independent School.)

From the earliest days, a great deal of work has gone into the school grounds and gardens which are a feature of the town. Mr Preston was gardener for 11 years, and must be given credit for much of what we see today. Within the grounds is a model of the Leeuwin Lighthouse built by the head cleaner, Mr J Todhunter. The lighthouse and motto ‘Shine Forth’ have been adopted as the school logo. The school farm commenced operations in 1956 to provide an increased range of relevant educational opportunities for students in Years 9 and 10. It currently involves 25 hectares where students can gain experience with animal husbandry, farm construction, crops and pastures, motors and machines and vineyard work. Livestock includes cattle, sheep, pigs and poultry for eggs.

Growth and development in the Margaret River district, coupled with an increasing retention of students into Year 11 and Year 12, indicate that Margaret River Senior High School has entered a new phase as the demand for Year 11 and 12 courses continues to grow. A Building Program saw the completion in July 1997 of a Design and Technology extension to accommodate Home Economics and Health Education. An Auditorium was built to cater for Dance, Drama, Music and Physical Education. The new Mathematics building includes 4 classrooms, a seminar room and computer resource area. Science also received a major extension and refurbishment and two new laboratories were built. A new administration block was built in 1999. The additions incorporate a Student Services Area and Medical Centre.

In 2011 Margaret River Senior High School became an Independent Public School. The School Council was replaced by a School Board and the school was able to gain greater flexibility with finances and staff selection.

In 2014 the State Government announced the move of Year 7 students into High School which would begin in 2015. As part of this move the school was given a building program that consisted of five general classrooms with a specialist Home Economics room.

In 2015, MRSHS received a $6.4 million Building Upgrade.

This has provided a new English faculty block that contains five standard classrooms, general activity space, a toilet block and a Food Science classroom.

The upgrade includes a 200 square metre undercover area which will is a home base for the Year 7 students.  For further recreational use there is an adjacent basketball court for student use.

2020 saw Margaret River Senior High School receive a $30 million redevelopment.

Two double-storey buildings and a sports hall are among the major new facilities officially opened by Education and Training Minister Sue Ellery.

One of the buildings includes 16 general classrooms and an inclusive education classroom, as well as staff study areas, storage space and toilets, to accommodate 550 students as the school population continues to grow. A dedicated science building also provides a new and innovative learning environment to match the school’s learning programs. The two-storey building includes five laboratories, preparation areas, study space for staff and storage areas. A brand new sports hall with a fitness centre, and change rooms will benefit staff and students alike, as sport, physical education and health are integral parts of the school’s education program. Other works include an extension to the administration building, as well as additions and upgrades to students’ services. Upgrades include new replacement farm workshops, a hay shed, horticulture and aquaculture facilities, storage and toilets.

The new facilities were officially opened by Education and Training Minister Sue Ellery.
Minister for Education & Training Hon. Sue Ellery MLC Offically opens the new facilities.