Fujitsu's club became professional in 1997, and changed its name – "Frontale" means "frontal" in Italian. The club old crest and colours are based on those of Brazilian side Grêmio, because both clubs have cooperated since 26 March 1997. The club joined the second division of the J. League in 1999, and became the champion of the division. But in the next season, it sank to the bottom of division one, and was relegated. In 2004, they were champions of J2 and won promotion to J1 for the second time. With the former rival city clubs out of the way due to relocation or liquidation, Frontale began building its power base in the city.
In 2006 they achieved runner-up position in J1, their highest league position to date. In 2007, this club attended the AFC Champions League, and made important success, as the first Japanese club for qualifying its group stage, before Urawa Red Diamonds. But Kawasaki lost in the quarter finals, against Iranian Sepahan, in a penalty shoot-out after two scoreless games.
Frontale's rivalry with FC Tokyo is known as the Tamagawa Clasico (using the Spanish word "Clasico" as used in derbies in Spain and Latin America). The two clubs first met in 1991 in the old Japan Soccer League Second Division and were rivals for promotion to the J. League in the 1990s. They co-founded the new J2 in 1999 and were promoted together the same year, and although Frontale were immediately relegated, they were promoted again in 2005 and have regularly met since then.
Frontale also has a Tamagawa rivalry with Tokyo Verdy 1969, which was originally also based in Kawasaki and moved to Chofu, Tokyo in 2000. The two were co-founders of the JSL Second Division in 1972 and, although spent 20 seasons (1979 to 1999) in separate tiers, rekindled the rivalry in the late 1990s as Kawasaki fans deserted Verdy to support Frontale, seen as a more community-focused club, and since then their fortunes have reversed as Frontale is a top flight mainstay while Verdy sunk into the second tier beginning in 2005.