William E. Peterson

William E. Peterson (February 2, 1936 – January 11, 2026) was an American politician and educator who served as a member of the Illinois Senate from 1993 to 2009. He also served as the Assistant Minority Leader.

Early life and career William E. Peterson was born on February 2, 1936, in Chicago. Peterson served on the school board in Elmwood Park, Illinois before moving to the north suburbs. He taught at schools in Northbrook and Highland Park. He graduated from Schurz High School in 1956. After receiving his associate’s degree from Wright Junior College, he enlisted in the United States Army. He was stationed for a time in Okinawa. He then completed his bachelor’s degree at North Park College in 1960, his Master's Degree in Education at Northern Illinois University in 1965. He served as supervisor while simultaneously serving in the Illinois General Assembly. He remained in the office after retiring from the Illinois Senate, retiring in 2017.

Illinois General Assembly Peterson previously served in the Illinois House of Representatives from 1983 to 1993. He served in the Illinois Senate from 1993 to 2009. For part of his time in the Illinois Senate, his committee responsibilities were: Senate Committee of all; Insurance; Human Services; Local Government; Housing and Community Affairs (Minority Spokesperson); Executive; Labor. Peterson had announced that he would not seek reelection in 2008. Republican candidate Dan Duffy of Lake Barrington defeated Bill Gentes, the mayor of Round Lake, in the November 4, 2008 election.

Death Peterson died on January 11, 2026, at the age of 89.