The 31-year-old Florida native, who played for seven teams across a nine-year career, confirmed the decision by releasing a statement to Sports Spectrum.
"It's time. I'm officially announcing my retirement from the game I love," Forsett said. "It's been an amazing ride and I'm grateful for every moment. My career has brought so many great people into my life, and I asked some of them to join me in saying goodbye."
Forsett also discussed his journey to making a major impact at the pro level. He was an undersized seventh-round pick of the Seattle Seahawks out of Cal in 2008 and served mostly in a reserve role until 2014, when he got a chance to start for the Baltimore Ravens and made the Pro Bowl.
"Against all odds, critics, and naysayers, I accomplished something great," he said. "Scouts measured my height and said I was too short. They measured my 40-yard dash and said I was too slow. They looked at my build and said I wouldn't last. But they couldn't measure my heart, my faith and my perseverance."
The versatile playmaker added: "I am living proof that dreams come true and God answers prayers, and I thank God everyday for the opportunity to live out my dream."
Forsett finishes his NFL career with 820 carries for 3,890 yards and 19 touchdowns. He added 210 catches for 1,351 yards and one TD as part of the passing game and made an impact on special teams during a nearly decadelong career.
His 4.7 yards per carry ranked tied for fourth with LeSean McCoy and DeAngelo Williams among active rushers prior to his retirement announcement.
Along with the Seahawks and Ravens, he made stops with the Indianapolis Colts, Houston Texans, Jacksonville Jaguars, Detroit Lions and, most recently, the Denver Broncos.