"It is inconceivable to me in a society that is so desperate for love and so desperate for closeness and so desperate for people to live peaceably with one another that anyone can turn their back on this legislation," Lang said. "All this legislation proposes to do is to let people be together in peace and in love and make the world a better place."
Next year's election also factored into the roll call. Two legislators vying to be the next state treasurer — Republican Rep. Tom Cross of Oswego and Democratic Sen. Mike Frerichs of Champaign — supported the measure.
"I think it says a lot about Illinoisans, I think it says a lot about Americans, I think it says a lot about where the country's going," sponsor Harris said. "You had Republicans voting for this bill, you had Democrats voting for this bill. You had folks from southern Illinois voting for this bill, from central Illinois, from the suburbs, from collar counties. You had African-Americans, you had Latinos, you had white, gay and straight."
Illinois is set to become the 15th state to legalize same-sex marriage.
It's unclear when the governor plans to sign the measure into law, but he hailed the vote as putting Illinois "on the right side of history."
Tribune reporter Rick Pearson contributed from Chicago.