Jon Duplantier attended Seven Lakes High School in Katy, Texas and played college baseball at Rice University. After missing the 2015 season due to a shoulder injury, he returned in 2016, and was named the Conference USA Pitcher of the Year.
Duplantier was drafted by the Arizona Diamondbacks in the third round of the 2016 Major League Baseball Draft. He made his professional debut with the Hillsboro Hops in June pf 2016, and struck out the side in his one inning there. He started 2017 with the Kane County Cougars and was later promoted to the Visalia Rawhide.