In 2007, his sophomore year of high school, he help his team advance into the semifinals at the 59th Hwarang Flag National High School Baseball Championship, racking up two wins as a starting pitcher.

Drafted by the Doosan Bears in the second round (39th pick, 47th overall) of the 2009 KBO Draft, Jung became the youngest position player in franchise history to be named to the Bears' Opening Day 26-man roster since Jung Soo-Keun in the 1995 season.

He made his pro league debut on April 5, 2009, as a pinch runner against the Kia Tigers.

He finished his rookie season with a respectable .264 batting average, 3 home runs, 17 RBI and 13 stolen bases in 85 games.

After the 2010 season, Jung was selected for the South Korea national baseball team to compete in the Intercontinental Cup held in Taichung.