Bears running back Tarik Cohen appeared to end the game with a 73-yard touchdown run earlier in OT, but officials determined he stepped out of bounds on the 37-yard line. Chicago challenged the call, but it was upheld by video replay.
Howard finished with 138 yards and two touchdowns as Chicago (1-2) won for the first time this season.
Pittsburgh (2-1) tied the game with 8:03 remaining after Chris Boswell connected on a 32-yard field goal after the Steelers picked off Mike Glennon deep in Bears territory. The Steelers got to within 17-14 with 6:43 remaining in the third quarter on a Le'Veon Bell 1-yard touchdown run.
The run came after the Steelers had their drive extended by a holding penalty in the end zone that gave Pittsburgh the ball at the Chicago 1-yard line.
The Bears led 17-7 at halftime after Glennon found Adam Shaheen open in the end zone on a two-yard touchdown pass with 43 seconds remaining in the second quarter.
Connor Barth extended the lead to 10 points with a 17-yard field goal with no time showing on the clock. The kick occurred after Chicago's Sherrick McManis blocked a Boswell field goal and Marcus Cooper recovered the ball and had a clear path to the end zone. But Cooper slowed down at the goal line and had the ball stripped by Vance McDonald before Cooper reached the end zone following a 73-yard return.
The Steelers batted the ball out of the back of the end zone for a touchback. But after video review the call was reversed and the batting of the ball was deemed illegal. The Bears were given an untimed down at the 1-yard line, but were called for a false start. That lined up Barth for the field goal that gave Chicago a 10-point lead.
The Bears forced a pair of first-quarter turnovers. After Pittsburgh's Eli Rogers muffed a punt, Howard gave the Bears a 7-0 lead with a three-yard run. Bryce Callahan stripped Ben Roethlisberger on a sack, but the Bears were unable to capitalize when Barth pushed a 47-yard field goal attempt wide right.
The Steelers tied the game at 7 when Roethlisberger connected with Antonio Brown for a 7-yard touchdown with 5:42 remaining in the first half.
Roethlisberger finished with 235 yards and a touchdown, Bell had 61 yards on 15 carries and Brown had 10 receptions for 110 yards and a touchdown.
NOTES: Steelers WR Antonio Brown became the fastest NFL player to reach 650 career receptions. Brown reached the mark in his 104th game, three fewer than former Indianapolis Colts receiver Marvin Harrison, who achieved the feat in 107 games. ... Steelers G Ramon Foster left the game with a hand injury. ... Bears LG Kyle Long played for the first time this season after recovering from ankle surgery. ... WR Markus Wheaton (pinkie surgery) and CB Prince Amukamara (ankle) also made their season debuts. ... TE Adam Shaheen scored his first career touchdown on a two-yard catch just before the half. ... Bears C Hroniss Grasu left the game with a wrist injury.