Pineiro finished the game 3-for-3 on field goal attempts, including a 52-yard conversion in the second quarter.
"It felt different. This was an emotional kick," Pineiro said afterwards. "With everything I've been through. The whole kicking situation. The Augusta silence. The media, everybody piling on."
The Bears (1-1) went 1-of-2 on 50-yard field goals last season. The last time Chicago made two 50-yard field goals in the same game was 2011 at the Oakland Raiders, according to ESPN Stats & Information.
The Bears settled on Pineiro to replace Cody Parkey after an exhaustive offseason search that at one point included nine place-kickers at the club's annual rookie minicamp in May.
The Bears traded for Pineiro in the spring after he spent last year on the Oakland Raiders' injured reserve list.
"I like rooting for good people and he's a good person," Bears coach Matt Nagy said. "He fought for a lot to get to this point. He listened to coaches, he trusted himself, and teammates that believe in him. Good things happen to good people. 42-yarder, 52-yarder, 53 to win the game. Can't make that up."
Pineiro, 24, is a perfect 4-for-4 on the season after nailing his lone attempt in last week's season-opening loss to the Green Bay Packers.
"Whenever you have a new guy come in, you want to see if that particular player has the 'dawg' in him -- meaning that raw, doesn't care, just going to go in there and compete persona," Bears cornerback Prince Amukamara said. "All throughout training camp, OTAs, we've just seen that in Eddy. He's always had ice in his veins. When he missed one, he was never shaken over it."
Bears guard Kyle Long compared Pineiro's game-winning field goal to the last-second 58-yarder kicked by the New Orleans Saints' Wil Lutz to beat the Houston Texans in Week 1.
"The 30 other teams not involved in that all watched that clip this week. We said before Eddy took the field for that game-winning kick, why not us?," Long said.
Trubisky's clutch pass, Pineiro's winning kick lift Bears past Broncos
Mitchell Trubisky's pass to Allen Robinson with one second left sets up Eddy Pineiro's game-winning 53-yard field goal as the Bears prevail 16-14.
Pineiro compares kicking with Bears to Florida
Eddy Pineiro describes the emotion around his game-winning kick and how kicking for the Bears resembles his time at Florida.