Tân Lêng-thong was born in Xizhi, Taipei. After graduating from Taoyuan Nankan Common School, he moved to Tamsui with his father, Reverand Tân Ōng, and enrolled in Tamsui Middle School (predecessor of Tamkang High School). After his graduation, Tân Lêng-thong went to Japan and studied at the Kumamoto Fifth High School in Kyushu. In 1927, he graduated from the College of Science at Kyoto Imperial University and later returned to Taiwan, teaching at Tamsui Middle School.

In 1937, Tân Lêng-thong pursued further study at the Japan School of Theology and graduated in 1940. He then taught at Chang Jung High School in Tainan, Taipei Theological College and Seminary, and Tamsui Middle School. He also served as a church pastor.

After the 228 Incident occurred, Tân Lêng-thong, as the principal of Tamsui Middle School, witnessed the exacerbation of the situation and decided to let boarding students from central and northern Taiwan return to their hometowns for safety. However, one student, Koeh Hiáu-cheng, did not go home and got shot and killed by soldiers on the streets of Tamsui. Tân Lêng-thong and N̂g A-thóng, the school’s director of educational affairs helped arrange funeral affairs. Upon returning home, Tân Lêng-thong told his son, “Do not go outside and participate in anything!” Sadly, these proved to be his final words.

Around 7 a.m. the following day (March 11), several soldiers, led by the school’s kitchen staff, went to Tân Lêng-thong’s residence and forcibly took him away from his bed while bulgarizing things in the house. His father, Tân Ōng, tried to chase after them but was also detained by the soldiers.

After Tân Lêng-thong and Tân Ōng were taken away by the soldiers, the Tân family made various efforts to find where they had been taken. On March 12, Tân Ōng was released, and it was only then that the family learned that they had been taken to the seaside (Shalun, Tamsui) and tied to tree trunks. Only Tân Ōng was released, while the whereabouts of the others remained unknown.

It was speculated that Tân Lêng-thong's trouble was due to the rifles for military education the the school, which the authorities believed were weapons to attack the government.