His eldest sister, Sandara, achieved nationwide fame in the Philippines in 2004 after becoming the runner-up on the first season of Star Circle Quest, a talent search reality competition.

Later on, as his sister began her hectic activities as a celebrity, a crew from one of South Korea's biggest television agencies recorded her daily life in the documentary My Name Is Sandara Park.

Sandara's eventual decision to pursue activities in their home country led to their family's return to South Korea in 2007.

It was later on revealed in a magazine interview that he had originally decided to pursue a professional career as a soccer player, specifically as a midfielder.

Thunder, Seung-ho, G.O, Lee Joon and Mir made their debut as MBLAQ on October 9, 2009, at Rain's Legend of Rainism concert where they performed various songs from their then-unreleased single album Just BLAQ.

[15] In March 2010, Thunder alongside U-KISS' Dongho and Eli and Shinee's Key hosted a new variety show called Raising Idol.

Also in April, Wanna Girls magazine named him as new fashionista icon of 2012, along with Jessica Jung, Hyomin and Yong Jun-hyung.

[28] In October, Thunder started his career in runway as he walked for Lee Jae-ho's Coexistence Collection in S/S 2013 Seoul Fashion Week.

[29] In November, he walked for Korean designer Park Jong-cheol's fashion show 'Bling Bling Party' as part of SUNY Korea Festival.

[30] In January 2013, Thunder was cast as the male lead in the MBC drama Nail Shop Paris, with Park Gyu-ri.

In 2016, he made a cameo appearance on another MBC drama, Woman with a Suitcase, as Cheondung, a lawyer interviewing for the same job as Ma Seok-woo (played by Lee Joon).

His self-titled debut extended play as a solo artist was released on December 7, 2016, and featured guest appearances by Goo Hara, Basick and Giantpink.