Schweigert is returning to Grand Forks after a decade away from the program. He was the defensive coordinator who helped North Dakota win the 2001 NCAA Division II national title.
"We will put for great effort to facilitate positive relations with fans, alumni, the community and the student body," Schweigert said in a statement. "We look forward to playing exciting championship football in front of thousands of loyal fans as we strive to win the Big Sky Conference championship and, ultimately, reach the pinnacle of FCS football."
Schweigert said he was looking forward to hiring a staff and building a program "that will represent UND in a first-class manner, both on and off the field."
The Zeeland native replaces Chris Mussman, who was fired after six seasons. North Dakota was 3-8 this year.
"Coach Schweigert brings a wealth of coaching experience, is a proven recruiter, an effective communicator and has an incredible passion for the game," North Dakota athletic director Brian Faison said.
Schweigert has been at Southern Illinois for six years, the last five as an associate head coach under Dale Lennon. He coached three first-team, All-Americans and 20 all-conference selections.
His defensive standouts have included linebacker Jayson DiManche, currently playing for the Cincinnati Bengals, and cornerback Korey Lindsey, a 2011 draft pick of the Bengals.
Schweigert previously was the head coach at Division II Minnesota Duluth from 2004 to 2007. He guided the Bulldogs to their first North Central Conference title. That came after 15 seasons as an assistant coach at North Dakota, the last five as defensive coordinator. He was part of eight NCAA playoff teams and six NCC title squads at North Dakota.
Schweigert began his coaching career at his alma mater, now Jamestown University, from 1985 to 1988. He earned a bachelor's degree in business administration from Jamestown and a master's degree from North Dakota.
A press conference to introduce Schweigert has the school's 26th head coach is scheduled for Friday morning at the Alerus Center.