[3] In 2001, he entered the SM Youth Best Contest and jointly won first place for the Best Outward Appearance award with future bandmate Donghae.

In 2002, along with Typhoon, Rose and Attack, the six of them made their first television appearance in a show called Heejun vs. Kangta, Battle of the Century: Pop vs. Rock.

The six trainees separated a year later, then Typhoon, Rose, and Attack debuted as members of rock band TRAX.

[5] Sungmin debuted as part of 12-member rotational group Super Junior 05 on 6 November 2005, on SBS' music programme Inkigayo, performing their first single, "Twins (Knock Out)".

[10] Sungmin guest starred in SBS' Banjun Theatre drama Finding Lost Time and played Yoochun's high school friend.

In 2009, he starred as male lead, Ro, in musical Akilla at the Hanjeon Art Center in Seoul from October 9 to November 8.

[14] In October, Sungmin was one of 20 South Korean singers selected to record the theme song, "Let's Go", for the 2010 G-20 Seoul summit.

In July and August, Sungmin performed as the male lead Daniel, rotating with Ahn Jae-wook, Um Ki-joon, and Lee Ji-hoon, in the musical Jack the Ripper at Chungmu Arts Hall.

[17] In 2012, Sungmin took part in We Got Married's spin-off program with Sistar's Hyorin called "Pit-a-Pat Shake" to air as a Lunar Year special.

[18] Sungmin along with bandmate Ryeowook, took over Super Junior's Kiss the Radio, when former DJs Leeteuk and Eunhyuk left due to their busy schedules.

On 29 March 2012, Sungmin released his first solo digital single, "Oh Wa", the ending theme song for KBS sitcom, We Need a Fairy.

[19] In September and October 2012, Sungmin reprised his role of Daniel, with Ahn Jae-wook, in the Korean musical Jack the Ripper and held its Japanese tour at Aoyama Theater in Tokyo, Japan.

[20][21] The musical was well-received and, due to its popularity, it was brought back to Japan for another run at the Kanagawa Arts Theatre in Yokohama the following year.

Japanese media noted that the impact of the Hallyu Wave in general and specifically the casting of Sungmin helped build popularity for the show in 2012.

[23] In June 2012, Sungmin reunited with his Super Junior bandmates for their sixth studio album, Sexy, Free & Single released on July 4.

On June 25, his teaser photo was released showing a side-profile of Sungmin with a feminine look and long blond hair holding a large bouquet of baby's breath flowers.

Sungmin continued participating in musicals, with a comeback in Summer Snow which was held in Taiwan for three consecutive days.

[2] He does a variety of shows, from answering letters sent in by fans to advertising different products he discovers, vlogs, video games and composing music.