Overcoming early challenges, including low enrolment, the school saw significant growth under new management, achieving a student body of over 670 by 1967.

Despite governmental changes affecting enrolment policies, the school adapted and expanded its offerings, including classes for the Malaysian Education Certificate and Pre-university studies.

Over the years, it has undergone numerous developments, including the construction of new buildings and facilities to enhance the educational experience.

Chong Fook Thien, then-President of the Hakka Association and one of the school's founders, proposed the construction of its building.

At the first meeting on 6 January 1965, the name "Sabah Tshung Tsin Secondary School" was decided.

Soon afterward, the school was approved by the state's Education Department and 9.26 acres (37,500 m2) of land was granted for its construction.

The Api-Api Hakka Association decided to take action and had appointed a new management for the school.

The Hakka Association tried to implement improvements for the school, independent of the Government because of the discrimination against Chinese High Schools due to the New Economic Policy, an affirmative policy which was introduced by the Malaysian Federal Government in 1971 favouring the bumiputras.

On 19 August 1984, a new five-storey Multipurpose Building was opened, which once housed the school canteen and a computer lab on the first floor.

The school's principal Chang Yu On died on 4 November 1989 of a heart attack at age 48.

In 1991, the Yang di-Pertua Negeri of Sabah, Mohammad Said Keruak bestowed the honorary title "Datuk" to Chang Yu On posthumously to honour his contributions to Chinese education in conjunction with his 66th birthday celebrations.

In March 1990, Tsen Kui On and Hiew Hoh Shin were chosen as vice-principals of the school.

Due to the increase in enrolments, the Hakka Association proposed to build a new school campus in Menggatal.

In 1997, the then Chief Minister of Sabah, Yong Teck Lee, approved a permit and a land title was received.

The new area was originally set to be served as the school's new campus of STTSS starting from 2002, but was not approved and the plan was proved as a failure.

In 2015, the School Heritage Centre(校史馆 pinyin: Xiào shǐguǎn) was officially launched on 1st August 2015, and is located in the fourth floor of the Multipurpose Building.In April 2017, a Rubber Running Track around the school football field was completed,[5][6] making future Sports Days' Running events better by providing extra traction.

[7][6] The new building, named TreeCube, has a recreational area on the ground floor and individual lockers for students.

In July 2017, the plea was approved, with Junior 3 students able to take Mathematics and Science in English for PT3 starting from 2019.

[8] A year later, a mini theatre, which is located at the fourth floor of the building and is able to accommodate about 180 people, was completed on 6 January 2023.

Tshung Tsin Night (崇正之夜 pinyin: Chóngzhèng zhī yè) is an annual public concert that is solely organized by the Co-Curriculum Activities Department of the school.

[13][14] In each concert, with an impressive turnout of at least 3000 attendees over the two performance days, Tshung Tsin Night creates a lively atmosphere.

The theme for the latest Tshung Tsin Night concert is "WANDERLUST", which is originated from German and can be defined as "the desire to explore unknown worlds".

It mainly focuses on the skill and immersion of singers who participated in the competition in order to decide the winner.

In addition to monitors having lunch with the form teachers, they will also exchange commemorative gifts and express their gratitude to each other on this event.

[19] In the 21st century, the building saw major reforms such as the conversion from the canteen, the lecture and the computer lab to numerous extra classrooms and a locker room in order to cope with the increasing number of students in the school.

Currently, the ground floor houses five extra classrooms, a photocopy shop, a resting room for teachers and several individual lockers, thus connecting with TreeCube, classroom buildings, the main school toilets and the newly constructed Locker Hub.

[21] Sabah Tshung Tsin Secondary School Library is a triple-storey air-conditioned library that occupies the second, third and fourth floor of the Multipurpose Building with a total floor area of 11,340 square feet, thus can accommodate 274 users at a time.

[24] The Yu On Court (Chinese: 佑安苑; pinyin: Yòu ān yuàn) is located next to the broadcasting room.

Students would visit the exhibition in an orderly manner, asking the university representatives about the admission needs and prerequisites of different departments.

Sabah Tshung Tsin Secondary School has co-organized 2024 China Higher Education Fair, which is participated by 16 Chinese colleges.