It's the first time Detroit (3-6) has won consecutive games in three years.
"Nobody in that locker room is saying we're awesome," Hanson said. "We're 3-6, but it does feel good to win two in a row."
Hanson, who has made all of this 13 field goal attempts this season, revealed his ritual before the game-deciding kick. "I pray. Not, 'God, let me make the kick,' because there are Bears praying that I'd miss. But I pray that I take the field without fear. I'm also trying to go numb, to be emotionless."
The Bears (3-6) had a chance to win three straight for the first time in two seasons and to end a road losing streak that now stands at 12 games.
"It's frustrating," Brian Urlacher said. "We didn't make a play all day."
Chris Chandler's 12-yard touchdown pass to Desmond Clark put Chicago ahead, 10-6, midway through the third quarter.
After falling behind for the first time, Detroit stalled deep in Bear territory for the third time and had to settle for another field goal.
The Lions kept Chicago's next drive alive with two penalties on third down, but Paul Edinger missed a 41-yard field-goal try.
Following two defensive stands, the Lions had the ball at their 35 with 2:27 left. Five Joey Harrington completions took them to the Bear 30.
"Once we got there, I felt terrific," said Harrington, who completed 24 of 38 passes for 238 yards.
After Hanson's kick, Corey Harris' diving interception at Detroit's 38 sealed the win.