Kai was the first EXO member to be formally introduced to the public through teaser trailers. His first teaser was released on December 23, 2011. He appeared in twelve more trailers released in the following three months, and had his first televised performance alongside fellow EXO members Luhan, Chen, and Tao.

In October 2012, Kai participated in the promotional group Younique Unit alongside label mates Eunhyuk, Henry, Hyoyeon, Taemin, and Luhan. The group released a single titled “Maxstep” as part of the collaboration between S.M. Entertainment and Hyundai. Later in December 2012, he joined the dance group S.M. The Performance, along with fellow member Lay, TVXQ’s Yunho, Super Junior’s Eunhyuk,  Donghae, SHINee’s Minho, and Taemin. The group first made its appearance at the event SBS Gayo Daejeon on December 29, and performed their single “Spectrum”. The single was officially released the next day.

In September 2013, Kai participated in a dance performance for Mnet’s dancing program Dancing 9, along with Lay and Girls’ Generation’s Hyoyeon, performing the songs “Centipede” of Knife Party and “Coco” of Gent & Jawns.

In August 2014, Kai was featured in the song “Pretty Boy” from SHINee member Taemin’s debut album. In January 2016, he made his official acting debut as the male lead in the web drama Choco Bank.The drama went on to achieve record breaking views.