JEF United Ichihara Chiba trace their roots back to 1946 as Furukawa Electric Football Club. They were one of the "Original Eight" founding members of the Japan Soccer League (JSL) in 1965 and enjoyed considerable success in the amateur era — two JSL titles, four Emperor's Cups, and three JSL Cups. In 1987, they won the Asian Club Championship (forerunner of the AFC Champions League), becoming the first Japanese club to be crowned champions of Asia.

In 1991, the club merged with JR East's football team. The name "JEF" combines the initials of JR East and Furukawa Electric, while "United" symbolises the union. As one of the "Original 10" clubs at the J.League's 1993 launch, JEF were a fixture in the top flight for 16 years. Under Ivica Osim in the mid-2000s, their high-energy, running-based football earned back-to-back Nabisco Cup titles (2005-2006) and Osim's philosophy became so influential that it was later called the "Osim Revolution" when he took charge of the Japan national team.

Relegation in 2009 began a long exile from the top flight. For 17 years, JEF competed in J2, coming heartbreakingly close to promotion on multiple occasions through the playoffs. In 2025, they finally earned their return to J1.

Under manager Yoshiyuki Kobayashi, JEF United dominated the early stages of the 2025 J2 season, racing into first place with a seven-point lead by the end of April. A dip in summer form saw them overtaken and they eventually finished 3rd, entering the promotion playoffs.

The playoff semi-final against RB Omiya Ardija provided one of the season's most dramatic moments: trailing 0-3, JEF staged a remarkable four-goal comeback to win 4-3. In the final, they defeated Tokushima Vortis 1-0 to seal promotion after 17 years away from J1. Kobayashi's emotional post-match interview became a viral sensation, hailed as "something every football supporter should hear."

A football-specific stadium in Chiba City's Soga district, opened in 2005 with a capacity of 19,781. The club originally played at Ichihara Rinkai Stadium before moving mid-season in 2005. Known affectionately as "Fukuari," the compact venue creates an intimate matchday atmosphere where fans are close to the action.