Jake Shields was born and raised in Mountain Ranch, a remote part of California's Sierra Nevada Mountains. As a child, he was homeschooled and had long hair, which made him a frequent target of other kids, leading to fights. With his older brothers, Shields was active in caving, mountain biking, and snowboarding. At age 9, Shields started competing in sports and took up wrestling, just like his older brothers.
As he grew older, Shields became a skilled wrestler and competitor, competing in the Amateur Athletic Union National Freestyle Championships and later qualifying for the U.S.A/Fila Nationals & World Team Trials in different divisions. Shields became a two-time All American at Cuesta College.
In 1999, Shields began training in MMA at SLO Kickboxing Academy after meeting its owner, Chuck Liddell, who encouraged him to try the sport. Shields' first professional MMA fight was at middleweight, despite being a natural welterweight, due to an injured teammate. He won his first two fights, but suffered his first defeat at the hands of Marty Armendarez.
Shields continued to compete in MMA, winning several fights and losing a few, including a loss to Phillip Miller. He then won several fights in a row, including a victory over Tracy Hess and a submission win over Jeremy Jackson. Shields decided to move down to welterweight and won his next several fights, including a victory over Robert Ferguson.
Shields' winning streak was ended by Ray Cooper, but he bounced back with a win over Hayato Sakurai in Shooto. Shields then won several fights in a row, including a victory over Akira Kikuchi, before losing to him in a rematch. Shields then won a few more fights, including a victory over Toby Imada, before entering a Grand Prix to become the welterweight champion at Rumble on the Rock 8.
Shields won the Grand Prix, defeating Dave Menne, Yushin Okami, and Carlos Condit along the way. He then won the Rumble on the Rock welterweight title, but never defended it. Shields then fought in Full Contact Promotions, beating Steve Berger and Ray Steinbeiss.
Shields signed with Elite XC and won several fights, including a victory over Renato Verissimo and a submission win over Mike Pyle. Shields then won the Elite XC welterweight title, defeating Nick Thompson with a guillotine choke. Shields defended the title against Paul Daley, submitting him in the first round.
After Elite XC closed, Shields signed with Strikeforce and won the middleweight title, defeating Jason Mayhem Miller. Shields then defended the title against Robbie Lawler, submitting him with a guillotine choke. Shields was released from his contract with Strikeforce and later signed with the Ultimate Fighting Championship (UFC).
