The legislation Rauner signed on Monday becomes law immediately.
The law extends some concussion-related measures already in place in high schools to elementary and middle schools and expands them. It includes private as well as public schools.
All schools also must create a plan for dealing with concussions.
State Sen. Kwame Raoul sponsored the measure after both of his teenage children suffered concussions. The Chicago Democrat said he saw the impact the injury had on their academic performance.
The Illinois High School Association, which oversees prep sports in the state, supported the measure.