Lee Sung Jae plays the love-struck Song Jung Geun in "Warm and Cozy. Song is the resort executive who was rescued by a Jeju Island diver and falls in love with her despite the vast difference in their economic backgrounds. He's endearing as a man who falls in love at a late age and is humbled by the indifference of the person he falls for. He comes up with several schemes to run into her and is even prepared to go to diving school to attract her attention.
Lee Sung Jae is funny in this comedy and that's not surprising since he launched his film career with the romantic comedy "Art Museum by the Zoo." There was a time when he only played romantic comedy roles. He's branched out since then, playing thugs and mountain climbers, widowers and villains, ballroom dancers and fugitives.
In "The Suspicious Housekeeper," he played a man who was clueless about the lives of his own children and needed help from his very suspicious housekeeper, played by Choi Ji Woo.
In "The King's Face" he played Seo In Guk's father and rival, King Seonjo." Despite being rivals in the drama, the two got on well off camera, as Lee Sung Jae repeatedly teased Seo In Guk.
When Lee Sung Jae plays a villain, he can really convey despicable. He played the villain Jo Gwan Woong in "Gu Family Book." He was the man who ruined Lee Yeon Hee's life and sentenced her to live in the courtesan house. He was so evil in that drama, viewers hated him.
But when the cameras stopped rolling, the drama's cast and crew said he was a pleasure to work with due to his sense of humor. The actor is known for being cheerful and silly on set.
Lee Seung Gi even described his "Gu Family Book" co-star as "cute" and said that Lee Sung Jae was so cute that he was once inspired to kiss him while he slept.
Lee Sung Jae is also known for being kind to younger actors. And when he appears on variety shows he is known for making funny and embarrassing statements.
So, the character of Song Jung Geun may be closer in some ways to the actor's real personality than a few of his previous roles. Except maybe for the part where women are indifferent to him.