[4] He split time during his first professional season between the Gulf Coast League Nationals and the Auburn Doubledays where he posted a combined 3–2 win–loss record and a 2.02 earned run average (ERA) in eight games between both teams.

On December 7, 2016, the Nationals traded Dunning, Reynaldo López, and Lucas Giolito to the Chicago White Sox for Adam Eaton.

[9] Dunning was called up to the active roster and made his MLB debut on August 19, 2020, striking out seven batters with just one walk in 41⁄3 innings in a 5–3 victory over the Detroit Tigers.

[13] On December 7, 2020, Chicago traded Dunning and Avery Weems to the Texas Rangers in exchange for Lance Lynn.

[14] On June 1, 2021, Dunning recorded his first major league hit, a single off of Colorado Rockies starter Germán Márquez.