Simandle received a Bachelor of Science in Engineering in 1971 from Princeton University.
He received a Diploma in Social Science in 1975 from the University of Stockholm in Sweden.
He received a Juris Doctor in 1976 from the University of Pennsylvania Law School.
After graduating from law school, Simandle served as a law clerk to Judge John F. Gerry of the United States District Court for the District of New Jersey for two years, and then as an Assistant United States Attorney at the U.S. Attorney's Office for the District of New Jersey from 1978 to 1983.
He served as Chief Judge from January 2, 2012, until he assumed senior status on May 31, 2017.