Spates' agreement will keep him as the Cougars' head coach through the 2020-21 season.
"We're extremely pleased with the progress that Jeremy Spates has made in building a quality program with quality young men while achieving national success," said Hewitt. "He is consistently placing wrestlers at the national tournament, and we believe he is not that far off from placing an entire team there. We're excited that he is willing and enthusiastic about remaining with SIUE."
SIUE was touted nationally for its 2018 recruiting class, earning top 25 honors from FloWrestling and Intermat.
Beginning this season, Spates leads SIUE wrestling into a new era as a member of the Mid-American Conference. SIUE had been a member of the Southern Conference since the 2012-13 season.
"People have asked if this is a stepping stone but when I came here, this is where I wanted to be," said Spates. "I wanted to return the program back to its glory days. I am thankful for Dr. Hewitt and the athletic department for the opportunity to continue building the program."
The Cougars have grown significantly under Spates' watch since David Devine earned a spot at the NCAA Division I Championships during the 2013-14 season. Since then, 10 SIUE wrestlers won SoCon Tournament titles and advanced to the NCAA Championships.
Jake Residori took it a step further during the 2016-17 season when he earned All-American status at 174 pounds. He became the first SIUE wrestler to earn Division I All-American status since SIUE Athletics Hall of Famer Tim Wright in 1987.
SIUE will release its 2018-19 schedule early next month.