In 2007, Yubin made her debut with the Wonder Girls a girl group managed by JYP Entertainment on September 7, 2007, with their comeback single "Tell Me" as the main rapper of the group, replacing former member Hyuna.
Although Yubin is known to most as just the rapper of the group, she occasionally also acts as an additional vocalist to the group, examples of which include "This Time" and "Wishing On A Star". Aside from performing with Wonder Girls, she has also been featured in several MVs, including labelmate 2PM's debut music video, "10 Jeom Manjeome 10 Jeom" and Shinhwa's Once In A Life Time. In addition, she has also been featured on several different artists' singles, like Shinhwa's Andy Lee, Lee Min-woo, Kim Bum-soo, and Chun G. It was also revealed that Yubin is interested in writing her own lyrics which she was able to showcase for the first time in Kim Bum-soo's song "Do You Know That?". Since then, she has also written her own raps on several other songs she has featured in and most recently, it was revealed that she had written the lyrics for "Girls Girls", "Me, In", and "Sweet Dreams" which can be found on Wonder Girls' second studio album Wonder World. Yubin wrote the song "Hey Boy" for Wonder Girls mini album "Wonder Party".
Before debut, Yubin, along with her former group Five Girls, were featured on a reality TV show on MTV called Diary of Five Girls. The show followed the group as they prepared for their debut. Due to financial difficulties with their company, the group was never able to officially debut and they have all since debuted under different record labels. She and the rest of her band mates from the Wonder Girls have been featured on a number of different variety and reality TV shows. This includes a total of four seasons of MTV Wonder Girls, Wonder Bakery, Welcome to Wonderland, and Made in Wonder Girls. Welcome to Wonderland and Made in Wonder Girls followed the girls on their concert tours, revealing many behind the scenes footage from the tours. Yubin had also made a short cameo in MBC's popular sitcom, Here He Comes. Then, after Sunye's marriage, she made her acting debut through OCN's new drama, The Virus, where she played the role of Lee Joo-yeong, a genius hacker and an IT specialist.