[2] The Greys won both halves of the 1993 season and defeated the Ohio Valley Redcoats in the playoffs to become the first champions of the Frontier League.

On Tuesday, October 27, 1998, O'Fallon, Missouri, Mayor Paul Renaud announced the new name of the team to be the "River City Rascals".

Hughes Ballpark at the Ozzie Smith Sports Complex in front of an overflow crowd of 4,173 (3,500 seat capacity).

Under Clark, a former St. Louis Cardinals slugger,[9] the team led the Frontier League in home runs, however only two pitchers had ERAs under 5.00.

[10] He was replaced by Neil Fiala, who led the team to a West Division title in 2000 before losing in the first round of the playoffs to the Evansville Otters.

His contract was purchased from the Memphis Redbirds on July 2, 2006, by the St. Louis Cardinals where he appeared out of the bullpen during the 2006 regular season.

His first major league pitch (July 3, 2006) was hit for a home run by Atlanta Braves left fielder Ryan Langerhans; Kinney finished the 2006 season winning a championship ring with the Cardinals as 2006 World Series Champions.

[6] Under Rumfield, pitching improved in 2008 and closer Mike Benacka recorded 13 saves and a 0.35 ERA in 22 games before signing with Oakland Athletics halfway through the season.

Despite the improvement from 2006 Rumfield was replaced by Chad Parker, who previously managed the Macon Music of the South Coast League.

[6] Offense was led by Chad Maddox (.307) and Ryan Wehrle (.317), and in August, Frontier League all-star Ernie Banks was acquired from the Washington Wild Things and hit .353 on the season.

[16] In 2013, the Rascals and the City of O'Fallon, Missouri came to an agreement to extend their lease at TR Hughes Ballpark through the 2022 season.

[17] However, in October 2018 the city of O'Fallon locked the Rascals out of CarShield Field and terminated the lease, citing a lack of payment.

[18] The dispute was resolved with a new one-year lease in January 2019, opening a path for the Rascals season to continue as scheduled.

[20] The Rascals defeated the Florence Freedom in a decisive Game 5 winning 7-5 thus securing the 2019 Championship in their final season.