III. 2014: Debut
Following two years of training, a vocal coach gave her the stage name "Joy". Joy was officially introduced as the fourth member of Red Velvet on July 29, 2014. Joy was the only member of the group who was not introduced as a part of SM Rookies, a pre-debut training team created by SM Entertainment. Red Velvet made their debut in August 2014 with the digital single "Happiness".
IIII. 2015–present: Solo activities (Acting and OSTs)
In June 2015, Joy began her first solo television activity with the fourth season of MBC variety show We Got Married, where she was paired with BtoB's Yook Sung-jae. Joy gained recognition for her participation and won the New Star Award and Best Couple Award at the 2015 MBC Entertainment Awards. Joy also released a duet with co-star Yook entitled "Young Love" in April 2016, with Joy receiving a songwriting credit for the song. Departing in May 2016, they became known as one of the longest-running and most popular couples in the show's history. In November 2016, Joy collaborated with Lim Seul-ong in a duet titled "Always In My Heart". The song reached number one on several charts and number ten on the Gaon Download Chart. In 2017, Joy made her acting debut as the female lead in tvN's music-based drama The Liar and His Lover. For her performance as lead actress, Joy received the Newcomer Award at the OSEN Cable TV Awards. Joy also released several OSTs through Stone Music for the drama: Yeowooya, I'm Okay, Your Days, Shiny Boy, Waiting For You, and The Way To Me. The drama is a South Korean adaptation of Kotomi Aoki's popular manga Kanojo wa Uso o Aishisugiteru.
In 2017, Joy would also perform under the alias of Bandabi on the singing variety contest show King of Mask Singer, where she won her first round of the competition. In 2018, Joy began her first fixed hosting position as the co-host of the second season of JTBC music variety show Sugar Man alongside top TV personalities Yoo Jae-suk, You Hee-yeol, and Park Na-rae. The revamp was a success, and rated higher than its initial season. In 2018, Joy would also star in her second drama, MBC's Tempted, loosely based on the French novel Les Liaisons dangereuses, and recorded its OST "OMG!". Joy received numerous award nominations for her performance including: Best Actress at the 2018 MBC Drama Awards, and the Popularity Award (Drama Actress) at The Seoul Awards. In July 2018, Joy was chosen as one of the hosts of Lifetime's new variety show Pajama Friends, alongside Song Ji-hyo and Jang Yoon-ju. Later that year in October 2018, Joy released the soundtrack song "Dream Me" (with Mark Lee) for the KBS drama The Ghost Detective.
In January 2019, it was announced that Joy was chosen to be the main host of Asia's most popular beauty program OnStyle's Get It Beauty, with former Pajama Friends co-host, Jang Yoon-ju. In December 2019, Joy became the sole female member of athletic variety show, Handsome Tigers, alongside Cha Eun-woo, Lee Sang-yoon and Seo Jang-hoon. After positive response in variety shows, Joy won the Best Female Variety Idol Award at the 2020 Brand Customer Loyalty Awards. In March 2020, Joy released her solo OST "Introduce Me A Good Person" for the soundtrack of tvN's Hospital Playlist. The song reached number one on multiple charts, number five on the Billboard Korea's K-Pop Hot 100 Chart, number six on the Gaon Digital Chart, and has surpassed 487 Million Digital Index Points on Gaon. It was nominated for the Song of the Year Daesang (Grand Prize) and Best OST Award at the Mnet Asian Music Awards, and for Best OST at the 30th Seoul Music Awards.
In April 2020, Joy participated alongside prominent Korean artists in the multi-collaboration project "Evergreen Tree" to support medical professionals during COVID-19. In May 2020, Joy featured on the title track of R&B artist Crush, with "Mayday" reaching number one on Genie, Bugs, Soribada, as well as the top of the Melon R&B/Soul Chart. In July 2020, Joy went on to be nominated as a soloist at the 2020 Melon Music Awards for the Top 10 Artist of the Year Bonsang (Main Prize). In December 2020, Joy was also nominated as a soloist for the Artist of the Year Daesang (Grand Prize) at the 2020 Genie Music Awards.
IIII. Digital Singles
[2016.04.16] Eolinae (Ae) (어린애(愛); Young Love) (Joy & Yook Sung Jae)
[2016.11.04] Ibyeoleul Baewosseo (Always In My Heart) (이별을 배웠어) (Im Seulong & Joy)
[2017.03.20] The Liar and His Lover OST Part.1
[2017.03.27] The Liar and His Lover OST Part.2
[2017.04.11] The Liar and His Lover OST Part.4
[2017.04.17] The Liar and His Lover OST Part.5
[2017.05.01] The Liar and His Lover OST Part.8
[2017.05.08] The Liar and His Lover OST Part.9
 SBS Descendants of the Sun (cameo)
 Naver TV The Boy Next Door (cameo)
 tvN The Liar and His Lover
 MBC The Great Seducer
 SBS Star King (Along with Seulgi)
 MBC We Got Married (Pair with Sungjae)