Apart from her group's activities, Sunny has participated in numerous side projects including original soundtracks, television variety shows, musical acting and radio hosting.

[7] After the outbreak of the Gulf War, Sunny and her family returned to South Korea and settled in Jongno-gu, Seoul.

[16] In 2009, Sunny released two songs—a solo track "Finally Now" for the interactive movie Story of Wine and a duet "It's Love" for the MBC's drama Heading to the Ground, with Girls' Generation's member Taeyeon.

[17][18] During 2009 and 2010, Sunny was a co-host for MTV Korea television music program The M with SS501's Kim Hyung-jun and 2AM's Im Seulong.

The reality program narrated a journey of a group of South Korean celebrities who were brought together to work and experience the agricultural and rural life.

[24] In January 2012, stepping into the field of voice-over for the first time, she was featured in the Korean-dubbed version of animated film The Outback.

Sunny found the recording process to be initially difficult, stating that because Miranda was such a "charismatic" and "strong" character, it was hard to express "with just [her] voice" as it would have been "a different story if [she] was showing the actions".

[29][30][31][32] During 2012–2013, Sunny was cast in her first musical, Catch Me If You Can, based on the true story and life of a con man named Frank Abagnale.

Shin Yeong-seon from The Chosun Ilbo noted on Sunny's ability to understand the character and praised her well-portrayal of Brenda's "exaggerated cuteness and flippant acting".

[40][41] In November 2014, her solo song, "First Kiss", was released as a part of musician Hwang Sung Je's Project Super Hero series.

[45][46][47][48] In April 2015, Sunny's voice was featured on indie-band Roof Top House's debut single "Heart Throbbing".

The purpose of the show is to create a one-on-one vocal battle between veteran singers in Korea and talented amateur vocalists.