Hultgren won by a 6 percentage point margin according to AP results, and regains the district for the Republicans who held the seat for 70 years -- and once belonged to Speaker Dennis Hastert -- before Foster took office.
Foster conceded just before 10 p.m.
Hultgren served as an Illinois State Senator in the 48th District and on the 95th District in the Illinois House. He has a background in both business and law.
The fiscal conservative may blend in with Tea Party initiatives focused on budget cuts and fiscal conservatism.