[1] Teugels was born in Londerzeel, Belgium and studied at the Catholic University of Louvain, where he received his licentiate in mathematics in 1963.
He moved to the US to pursue further study and obtained his MSc in 1966 and PhD in 1967, both at Purdue University, where he was supervised by Marcel F.
[2] He returned to Belgium in the same year and took up a faculty position at KU Leuven, where he was promoted to full professorship in 1973.
During this period, Teugels was the chair of the Department of Mathematics from 1970 to 1977 and from 1982 to 1989.
[1][3] Teugels was named a distinguished alumnus of Purdue University in 2004.