His drama Daemul about Korea's first female president was also very popular during its run, staying atop TV charts for 11 weeks straight and ending with viewership ratings of around 26 percent.
Once Upon a Time in High School portrays the authoritarian society of the 1970s through a notoriously violent high school.
Simultaneously, his TV drama Stairway to Heaven was winning over high ratings on TV.
The drama was eventually screened throughout Asia and helped to turn him into a regional star.
However Kwon's followup film Love, So Divine, about a priest in training who falls in love, earned poor reviews and did not get much attention from audiences.
In this year he also starred in My Good Partner, the world's first movie made for mobile phones, and in the music video collection Project X.
His next film released in early 2004 was also a great hit.
For 2006, Kwon starred in the big-budget action noir Running Wild, about a detective, a prosecutor, and a criminal who are all equally vicious.
The following year he played his first lead role in the comedy Make It Big together with real-life best friend Song Seung-heon.Kwon's breakthrough came in the phenomenally successful comedy My Tutor Friend, as a troublesome high school boy who is tutored by a college student of the same age (played by actress Kim Ha-neul).Kwon Sang-woo, the most visible example of the so-called "mom-zzang" (slang for "great body") movement, started his career as a fashion model in the late 1990s.His first acting experience was in the TV drama Delicious Proposal, and for the first few years of his entertainment career he received only minor roles on television, before debuting in Volcano High (2001).
Thus began Kwon's career slump, as the films Fate and More Than Blue flopped in the box office, and his small screen projects Sad Love Story, Bad Love and Cinderella Man received low ratings.
Things took a turn for the better in 2010 with the box office success of Korean War film 71: Into the Fire which Kwon reportedly didn't hesitate to take on.