He has previously played in MLB for the Los Angeles Dodgers, Miami Marlins, New York Yankees, Tampa Bay Rays, and Boston Red Sox.

Eovaldi had Tommy John surgery to repair the ulnar collateral ligament in his right elbow during his junior year of high school.

[4] Eovaldi was promoted to the Chattanooga Lookouts of the Double–A Southern League in 2011 and was selected to the mid-season all-star game.

[5] Eovaldi was called up to the majors for the first time on August 6, 2011, and was the starting pitcher that night against the Arizona Diamondbacks.

[7] Eovaldi became the first Dodger starter since Danny McDevitt in the 1957 season to start his career with four games of five innings or more while allowing two runs or fewer.

[11] On July 25, 2012, Eovaldi was traded, along with minor league pitcher Scott McGough, to the Miami Marlins for Hanley Ramírez and Randy Choate.

[13] On December 19, 2014, the Marlins traded Eovaldi, Garrett Jones, and Domingo Germán to the New York Yankees for Martín Prado and David Phelps.

[14] Eovaldi made his first start for the Yankees on April 10, 2015, against the Boston Red Sox, where he pitched 5+1⁄3 innings, allowing two runs on eight hits.

[19] On August 16, 2016, it was announced that Eovaldi would miss the remainder of the 2016 season due to a torn flexor tendon and partially-torn ulnar collateral ligament in his pitching (right) elbow.

On July 25, 2018, the Rays traded Eovaldi to the Boston Red Sox in exchange for Jalen Beeks.

[30] In Game 3 of the League Championship Series against the Houston Astros, Eovaldi pitched six innings, allowing just two runs, as the Red Sox won 8–2.

Eovaldi threw 97 pitches over six innings of relief before giving up a walk-off home run to Max Muncy, which made him the losing pitcher.

[42] Eovaldi made four relief appearances with Boston in late July, allowing five earned runs in 3+2⁄3 innings pitched.

The Red Sox subsequently listed Brandon Workman as the closer on the team's depth chart.

For the 2020 season, Eovaldi was named Boston's Opening Day starter (delayed into July due to the COVID-19 pandemic) by manager Ron Roenicke.

[46] Eovaldi got the win in that game, pitching six innings while allowing five hits and one run, while striking out four batters, as the Red Sox defeated the Baltimore Orioles, 13–2.

[49] Overall with the 2020 Red Sox, Eovaldi appeared in nine games (all starts), compiling a 4–2 record with 3.72 ERA and 52 strikeouts in 48+1⁄3 innings pitched.

[11] Eovaldi was Boston's Opening Day starter for the second year in a row,[50] taking the loss as the Red Sox fell to the Orioles, 3–0.

[54] Eovaldi was the winning pitcher in the AL Wild Card Game, striking out eight batters and giving up four hits and one run in 5+1⁄3 innings over the Yankees.

[11] Eovaldi finished fourth in American League Cy Young Award voting after the season.

[59] On May 28, Eovaldi threw his first major-league complete game in a 5–3 win against the Baltimore Orioles—he allowed seven hits, two earned runs, struck out six batters, and only issued one walk while throwing 108 pitches.

[62] Eovaldi returned to the injured list on August 23, due to right shoulder inflammation;[63] he rejoined the team on September 29.

[65] On December 27, 2022, Eovaldi signed a two-year contract, with a third year vesting player option, with the Texas Rangers worth $34 million guaranteed.

The amount of weak bat-to-ball contact that Eovaldi generates is due to the difficulty of predicting which of his five distinct pitches will be thrown at a given time, leading even the most accomplished hitters to guess incorrectly and swing at a slow curveball when expecting a splitter, for example.