Thomas Weiss spent his early years in Nazareth and Easton. After attending school at the former place for a number of years, he took charge of his father's farming and lumbering interests. He was an energetic and enterprising citizen, and was active in promoting a number of the important public enterprises of his day. He commended the public-school system to the farmers of his locality, putting forth every effort in his power in behalf of public education, but met with considerable opposition among the German residents of the locality, who did not favor that method of instructing the young. After the completion of the Lehigh canal, Mr. Weiss, in connection with his brother, Francis, laid out the town of Weissport.

Thomas Weiss married Maria Solt, and they had eight children.