[3] When he was eight years old, Thomson moved with his family to the U.S.A.[2] In 1935 he graduated from Columbia University with a bachelor's degree, majoring in botany and zoology.
After receiving his Ph.D., he worked as a naturalist at Manhattan's American Museum of Natural History and taught at Brooklyn College until 1942.
[4] During WW II, he taught topics in military aviation and meteorology from 1942 to 1944 for the U.S. Army Air Corps at Superior State Teachers College (now named the University of Wisconsin–Superior).
[7] He collected lichens not only in the Arctic and in Wisconsin, but also in a number of other U.S. states, including "California, Florida, Indiana, Oklahoma, New York, Pennsylvania, and Washington".
[11][5] Upon his death he was survived by his widow, three sons, Dennis, Norman, and Roderic, a daughter, Elizabeth, and seven grandchildren.