A three-time All-Star, he was named World Series MVP with the Twins in 1987 and won the AL Cy Young Award in 1988.

Although his statistics were fairly disappointing—he finished 11–25 with a 5.37 ERA in the 1982 and 1983 seasons—Viola became a permanent fixture of the Twins' starting staff for the next 7 seasons, picking up 112 of his 176 career wins.

That year, he threw his signature circle change with skill, compiling an impressive 24–7 record with 7 complete games and 2 shutouts in 255 innings pitched with a career-low ERA of 2.64.

He would finish third in the Cy Young Award voting behind Pittsburgh's Doug Drabek and Los Angeles' Ramón Martínez, and he was named to the National League's All-Star Team.

In a spring training game on April 2, 1993, Viola and Cory Bailey combined on a no-hitter as the Red Sox defeated the Phillies 10–0 at Jack Russell Memorial Stadium in Clearwater, Florida.

After getting past the Detroit Tigers in the 1987 American League Championship Series, Viola and the Twins had to face the favored Cardinals.

Frank was also a part-time, substitute game broadcast announcer for NESN, network of the Boston Red Sox.

On January 26, 2011, Viola was hired as pitching coach of the Brooklyn Cyclones, the Mets' Single-A (Short Season) team.

[6] During a 2014 spring training physical, Viola was diagnosed with a heart condition that required open-heart surgery on April 2.

[11][12] He joined the High Point Rockers of the Atlantic League of Professional Baseball as the pitching coach in 2019,[13] a position he continues to hold in 2024.

Frank III struggled with injuries (including needing Tommy John surgery) and only pitched in 24 games at rookie level Bristol White Sox before being released following the 2007 season.

[18] He now serves as analyst for Bright House Sports Network on their studio show and for their Florida State League broadcasts.

Starting in 2012, Frank III has worked with R. A. Dickey and Hall of Fame pitcher Phil Niekro on developing a knuckleball to resurrect his baseball career.

[17] In December 2012, he appeared as himself on the How I Met Your Mother episode "The Final Page", where he is on the phone with Marshall, one of the main characters.