[3][4] On the evening preliminaries, Jeong rounded out the semifinal field by taking the final spot in a lifetime best of 2:27.28, just half a second (0.50) faster than her entry time.

[7] At the 2009 FINA World Championships in Rome, Italy, Jeong matched her preliminary heat time of 2:25.00 in the semifinals, but finished only in twelfth place.

[8] Six months later, she edged out her teammate Jung Seul-ki to take a silver medal by a two-tenth margin (0.20) in the same discipline at the East Asian Games in Hong Kong, China, breaking her personal best of 2:24.90.

[9] At the 2010 Asian Games in Guangzhou, Jeong picked up the women's 200 m breaststroke title in 2:25.02, beating two Chinese swimmers for the silver and bronze medals.

[13] Jeong shared a fourteenth-fastest qualifying time of 2:26.83 with Russia's Yuliya Efimova in the morning's preliminary heats to secure a spot for the semifinals.