Park made her official acting debut in the 2006 high school television series Secret Campus alongside fellow newcomer Lee Min-ho. Among the notable projects during the early stage in her career are historical epic The King and I and Peabody Award-winning teen drama Jungle Fish with Kim Soo-hyun, which was based on a true story that depicts the pressures placed on students to achieve and gain admission to prestigious colleges and universities.

Park rose to fame after starring opposite Cha Tae-hyun in comedy Speedy Scandal (also known as Scandal Makers), which drew 8.3 million viewers to become the number one top grosser of 2008 and one of Korean cinema’s biggest hits. Described by Variety as “excellent” in her role as a spunky teenage mom, Park’s much-praised performance swept Best New Actress awards in 2009. She has been dubbed as “Nation’s Little Sister” because of the success of the movie.Park then starred in a short film directed by Lee Hyun-seung, human rights-themed omnibus If You Were Me 4 in 2009.

However, in 2010 Park became involved in a series of legal disputes with her then-management agency and a film production company, causing the actress to be tied up in lawsuits and unable to work for the next few years.[