In February 1997, Sagan was established as a new club which virtually took over
Tosu Futures, which became insolvent in the previous month. They were admitted to participate in the
Japan Football League from 1997 to 1998, as well as the
J. League Cup in 1997 as a preferential measure, although
J. League Associate Membership status was not awarded to Sagan. In 1999, they were admitted to the new J. League Division 2 (J2) as one of the "Original Ten," which were the ten first members of the J2. They remained at that league until their promotion to J1 at the end of the 2011 season. Little by little, Sagan Tosu started to establish itself as one of the top clubs in the country with the new President &
Chief Operating Officer Minoru Takehara, who is also part owner of the club. In their first season at the
J1 League in
2012, confounding the prediction of many critics about their immediate relegation to J2, they maintained their position between 5th and 11th place all the way through the season, except on matchweek 2, in which they were ranked 13th. They were ranked third after the 33rd week, having a chance to qualify for the
2013 AFC Champions League if they hadn't lost to
Yokohama F. Marinos in the last match of the season. However, they only lost to Yokohama by 0–1, wrapping up the season in 5th place, while
Urawa Red Diamonds defeated
Nagoya Grampus and were ranked 3rd. They also became the first club in Asia to sign a partnership with
Warrior Sports, who sponsor many overseas clubs, including English side
Liverpool. In 2013, they made it to the semi-finals of the
Emperor's Cup for the first time in the club's history, becoming the first club based in
Kyushu to make it to the semi-finals of the
Emperor's Cup since
Nippon Steel Yawata had done so in the
1981 edition. In 2013, they invited the
A-League team
Sydney FC along with the former
Italian international player
Alessandro Del Piero for a Japan Tour for the first time. In 2014, the club had their most successful season in the
J1 League, being ranked on the top of the
2014 J1 League on the 1st, 2nd, 13th, and 18th matchweek. However, the club suddenly made an announcement on the 8th of August which announced the termination of the contract with the head coach Yoon Jung-Hwan, despite the apparently good season. During the course of the year, they continued on their international expansion and started a partnership with the Italian side
Juventus for its Juventus Under-16 Japan Tour 2014. On 10 July 2018, the club reached an agreement with former FIFA World Cup, UEFA Champions League and UEFA Europa League winner,
Fernando Torres. The aging star would play 35 games for the side, netting 5 goals before finally hanging up his boots on his star-studded career. On 19 October 2024, Sagan Tosu officially relegated to J2 League after defeat from
Kyoto Sanga 2-0 and return to second tier after 13 years absence with four games left, ended in top tier at 13 years stint. ==Kit and colours ==