"Now, although football has been a really great part of my life for the past 18 years, it is with the utmost regard and appreciation that I officially announce my retirement from the National Football League," he wrote.
Gould, 41, ranks 10th in league history in points scored (1,961) and eighth in field goals made (447). His 86.4% career success rate on his field goal attempts is ninth all time.
Gould was one of the first free agents signed by the San Francisco 49ers after coach Kyle Shanahan and general manager John Lynch took over in 2017. Since then, he remained one of the most consistent kickers in the NFL and became one of the league's all-time leading scorers.
"It didn't take more than two words to convince me that I wanted to play in that city," he wrote. "Kyle. Shanahan. His personal talent as arguably the best coach in the business, combined with that offense? I had zero hesitation about wanting to be a part of that culture. San Francisco may not have had the best record at the time, but the thought of what that team could become from a long-term perspective was impressive to me."
Last season, Gould was 27-of-32 on field goals and 50-of-51 on extra points on his way to moving into second place in field goals (161) and fourth in scoring (704) in Niners history.
He also was clutch in the playoffs throughout his career, making all 29 field goal attempts, including eight in 2022, and 39 PATs.
He wrote that his most memorable kick came in a playoff game at the Green Bay Packers in January 2022, when he kicked a 45-yard field goal with four seconds left to lift the 49ers to the NFC Championship Game.
"We didn't win it all or even make it to the Super Bowl that season, but, man, that one felt good. I've always had a healthy respect for the Packers and that fierce Bears-Packers rivalry. More than anything, though, I just absolutely love Bears fans," he wrote. "So, to hit a huge kick like that, on the big stage, to continue my streak of never missing a kick in the playoffs and to also make all of Chicago happy in the process by taking down its rival? It was the best of both worlds."
The Niners used the franchise tag on Gould in 2019, but the 49ers drafted kicker Jake Moody in the third round, moving on from their longtime kicker in favor of the rookie.
Before signing with San Francisco, Gould spent 10 seasons with the Bears and one season with the New York Giants. He was a Pro Bowl selection in 2006. He is the Bears' all-time leading scorer with 1,207 points.
"From start to finish, I loved everything about my time in Chicago," Gould wrote for The Players' Tribune. "... We had some deep playoff runs, and we made a ton of memories. The McCaskey family gave me the opportunity to live out my childhood dream, and it was an honor to play for them. Ultimately, I hope that we made Bears fans proud. They deserve it."
Gould added that Chicago "became my home." It's where he met his wife, and they have raised their three children in the city.
"My favorite team has been waiting for me at home to join them full-time -- no contract needed. I'm excited to be more present with my family and to focus all of my attention on what matters to me outside of football. For the longest time, my career has naturally filled my schedule, and my wife has taken the reins at home. My oldest is 10 years old, and I've been away from him for large chunks of nine years. My younger two boys are eight and five. For most of their lives, Dad hasn't been fully present. So, without interruption, I'm ready for this next stage of life," he wrote.
ESPN's Nick Wagoner contributed to this report.