Thanomseng Teso was born October 4, 1959, to Nim Teso and Lansy Samvong in Savannakhet, Laos. He immigrated to the United States in 1979 where he initially lived in Seattle, Washington. Thanomseng moved to Pella, Iowa, in 2005, where he worked for PPI (Precision Pulley and Idler) until 2021, when he retired.

Thanomseng married Vatsana Sisavath in 2011, and they had a daughter Angela in 2012. His parents have passed away, but he is survived by his two sisters and five brothers.

He enjoyed cycling and race cars and loved spending time with his wife and daughter.