Yang Dong-geun began acting in 1987 when he was only eight years old. In 1991, he appeared in the KBS2 drama Hyung, which won him Best Young Actor at the 27th Baeksang Arts Awards and the KBS Drama Awards. In 2001, he starred in director Kim Ki-duk’s film Address Unknown, which gave him the Best New Actor trophy at the 21st Korean Association of Film Critics Awards. That same year, he received a Top Excellence Award at the MBC Entertainment Awards for the sitcom New Nonstop. In 2002, he acted alongside Lee Na-young in the MBC series Ruler of Your Own World, which earned him numerous acting citations, including Best New Actor for TV at the 39th Baeksang Arts Awards. In 2004, he was named Most Popular Actor at the 27th Golden Cinematography Awards for the crime-drama film Wild Card. In 2017, he worked with Park Han-byul in the MBC variety-drama Borg Mom, which scored him a Special Award at the MBC Entertainment Awards.

Yang Dong-geun also ventured into hip-hop music, dropping his first studio album titled Yangdonggeun AKA Madman in 2001. He has since released several more albums such as But I Give in 2007 and YDG Series VOL. 1 JAJAJA in 2014. He has also collaborated with many artists over the years.

Yang Dong-geun attended Yongin University’s theater department. He enlisted for his mandatory military service in May 2008 and was discharged in March 2010. He married his girlfriend named Park Ga-ram in 2013 and also became a father to a son that same year. The couple has two sons and one daughter together.