Following this, on October 1, 1998, companies like Tokyo Gas, TEPCO, ampm, TV Tokyo, and Culture Convenience Club, set up a joint company Tokyo Football Club Company with the aim of making the team eligible for joining the J. League. In 1999, the same year the team became eligible, it won the J2 championship and joined the J1 league beginning in the 2000 season. Despite a widespread belief that the team would barely win enough to stay in the J1, the team won four games in a row since its opening game and managed to finish at the 7th spot.
Tokyo Dorompa, the club's mascot
Helped by its winning record, the attendance shot up and it is still above that of well-known Tokyo Verdy 1969 that moved its home town from Kawasaki, Kanagawa in 2001. Since 2002, the team welcomed Hiromi Hara as its manager and aimed for a championship with a strong offense. The 2003 season had the team finish in 4th, its highest ever. In August of the same year, it held a friendly match against one of the greatest football clubs, Real Madrid losing three-nil but gaining valuable experiences both on and off the field for what it takes to be a great football club.
Long-time leader Amaral, nicknamed The King of Tokyo by his fans, departed the team to join Shonan Bellmare in 2004. He was replaced by Athens Olympics national football team player Yasuyuki Konno from Consadole Sapporo. In November of the same year, it won the J. League Yamazaki Nabisco Cup for its first major title since joining the J. League.
Today the main sponsorship is done by ENEOS, another fuel company.