Happy Songs--SJ-H

By 2008, all of the Super Junior members have already been a member of at least one subgroup except Kibum. Super Junior-Happy consists of every previous member from Super Junior-T except Heechul, who is replaced by Yesung. Super Junior-Happy made an unofficial debut performance on May 3, 2008 at the Power Concert although they had not formally introduced themselves as the subgroup at the time.

On May 30, 2008, SM Entertainment released the official announcement of the subgroup through Newsen. The subgroup's first EP, Cooking? Cooking!, was released on June 5, 2008. The music video of their first single, "Cooking? Cooking!" was released on that same day.

Super Junior-Happy debuted on June 7, 2008, performing their first single, "Cooking? Cooking!" at the 2008 Dream Concert. On the day before their debut, the subgroup held their first sign fan meeting to celebrate the success of the sales of Cooking? Cooking! On the morning of June 6, over thousands of fans lined up for tickets to the fan meet, overcrowding the streets. Close to 10,000 copies were sold by the first week of release. According to the Music Industry Association of Korea, the EP sold 27,122 by the end of August and was ranked fifth in the monthly charts.

Super Junior-Happy performed their second single, "Pajama Party" on August 3, 2008 on SBS's Popular Songs. The music video was released on August 4, 2008. "Pajama Party" promotions only lasted a month, and promotions for the EP officially ended on September 7, 2008.

Super Junior-Happy's music style involves the common style of contemporary dance music and bubblegum pop, mainly targeting the music industry with their fun and entertaining style. Super Junior-Happy's debut single, "Cooking? Cooking!" is a dance track with refreshing rhythm and quirky lyrics. Their goal is to give fans feelings of bliss and happiness with their music.