Kingham started the 2013 season with the High-A Bradenton Marauders and was promoted to Double-A Altoona Curve during the season.[5] He was voted to the 2013 Florida State League All-Star Game.[6] He spent the 2014 season with Altoona and the Triple-A Indianapolis Indians. Kingham was added to the 40-man roster on November 20, 2014.[7]
Prior to the 2015 season, Kingham was ranked as the 67th best prospect in baseball by Baseball Prospectus.[8] Kingham underwent Tommy John surgery in May 2015.[9] He would miss the rest of the 2015 season before returning to make rehab starts in July 2016.[10] Kingham finished the 2016 season with 10 starts across the rookie, Class A and Class AA levels.[11] In 2017, Kingham suffered an ankle injury during spring training which delayed his season debut until May.[12]
Kingham began the 2018 season with Indianapolis. He was named International League Pitcher of the Week on April 16, 2018.[13] Kingham made his major league debut on April 29, 2018, against the St. Louis Cardinals. During his debut, Kingham took a perfect game through 6 2/3 innings before allowing a single to Paul DeJong. Kingham went on to record his first career win as the Pirates won 5–0.[14][15]
On April 30, 2018, Pirates manager Clint Hurdle announced that Kingham would remain in the Pirates rotation, with Steven Brault moving to the bullpen to make room.[16] In 18 games (15 starts), he finished 5–7 with an ERA of 5.21 in 76 innings.
Kingham began 2019 in Pittsburgh's bullpen before moving to the starting rotation. He was moved back to the bullpen in May.[17] He was designated for assignment on June 8 after going 1–1 with a 9.87 ERA in 34.2 innings.[18]
Toronto Blue Jays
Kingham was traded to the Toronto Blue Jays on June 13 for cash considerations,[19] activated on June 15, was designated for assignment on July 18 and outrighted to Triple-A Buffalo on July 21.[20] He rejoined the Blue Jays on August 2.[21] On August 25, Kingham was designated for assignment and released on August 26.
SK Wyverns
On November 28, 2019, Kingham signed a one-year contract with the SK Wyverns of the KBO League.[22] On July 2, 2020, Kingham was released by the Wyverns.
Hanwha Eagles
On November 28, 2020, Kingham signed a one-year contract with the Hanwha Eagles of the KBO League, worth $250,000 and a $100,000 signing bonus.[23] He made 25 starts for Hanwha in 2021, pitching to a 10–8 record and 3.19 ERA with 131 strikeouts in 144.0 innings pitched.
On December 28, 2021, Kingham re-signed with the Eagles for the 2022 season for $900,000.[24] He made 3 starts for the team, logging a 1–2 record and 2.76 ERA with 18 strikeouts in 16.1 innings of work. The Eagles released Kingham on June 2, 2022, due to an arm injury.[25]
Diablos Rojos del México
On February 27, 2023, Kingham signed with the Diablos Rojos del México of the Mexican League.[26] He made one start, giving up 2 earned runs in 5.0 innings pitched. On May 2, Kingham was released in order to pursue an opportunity in Asia.[27]
CTBC Brothers
On May 3, 2023, Kingham signed with the CTBC Brothers of the Chinese Professional Baseball League (CPBL).[28] In 5 starts for the Brothers, he went 3–0 with a 7.71 ERA and 13 strikeouts in 23+1⁄3 innings pitched. On July 13, Kingham was released by the club. It was subsequently reported that the release was a result of Kingham deciding to retire from professional baseball.[29]
