Marin has a Ph.D. and a master's of arts in mathematics, both from Bowling Green (Ohio) State University. He has a bachelor of arts in mathematics from Franklin and Marshall College, Lancaster, Pennsylvania. Prior to joining the Finlandia faculty, Marin was an assistant professor of mathematics at Alfred University, Alfred, New York.
As a teacher, Marin works to inspire and guide his students to discover for themselves the wonder of mathematics. He tries to teach his students by encouraging them to discuss math with him as often as possible. Marin and his wife, Kate, have three young children, Juan III, Roberto, Andres, and Elena. They live in Hancock and enjoy canoeing and the outdoors.