John graduated cum laude from Rockhurst College in 1972 with an A.B. degree in History and was a member of Alpha Sigma Nu, the Jesuit honor society.

In 1975, he graduated from Drake University Law School and was admitted to the Iowa Bar in June 1975. He served as a staff attorney with the Polk County Offender Advocate Office from July 1975 until March 1979, representing indigent defendants in criminal cases. He tried numerous felony and indictable misdemeanor cases.

He also served as a staff attorney in the Environmental Law Division of the Attorney General’s Office from March 1979 to January 1983. From January 1983 to January 1991, he was in charge of the Environmental Law Division.

John assumed the responsibilities of County Attorney in January 1991 and was re-elected in 1994, 1998, 2002, 2006 and 2010. He was President of the Iowa County Attorneys Association in 1998, and is currently a member of the Board of the Iowa County Attorneys Association. John was the Iowa State Director of the National District Attorneys Association from 1998 to 2000, and is a member of the NDAA Board of Directors, and co-chair of the NDAA Legislative Committee.

He and his wife Nancy have three adult children.