Born in Des Moines, Iowa, Wangelin received an Associate of Arts degree from Iberia Academy and Junior College in 1932 and a Juris Doctor from the University of Missouri School of Law in 1936.
He was a Lieutenant (SG) in the United States Navy during World War II, from 1942 to 1945.
He then returned to private practice in Poplar Bluff, Missouri, until 1970.
[1] On December 8, 1970, Wangelin was nominated by President Richard Nixon to a joint seat on the United States District Court for the Eastern District of Missouri and the United States District Court for the Western District of Missouri vacated by Juge Roy Winfield Harper.
He assumed senior status on May 10, 1983, serving in that capacity until his death on June 10, 1987, in Poplar Bluff.