Xinmin was founded as Sin Min Public School (公立新民学校) by Yap Fun Hong.

[a] Yap sold five of his pigs in order to raise money to buy three bungalows along Upper Serangoon Road.

[8] Between 1992 and 1997, Xinmin Secondary School underwent changes to its curriculum under principal Goh Tong Pak, which included stricter rules and fostering of an inclusive culture.

[13] In 2010, in celebration of her 65th anniversary, Xinmin Secondary School broke the Singapore Book of Records by building the largest sculpture out of recycled cans.

Funds were raised by students through the annual Homecoming Day celebrations along with significant donations by notable alumni such as Dr George Quek, the founder and CEO of BreadTalk, and Chua Kee Teang of Mukim Investment.