Question: Who plays eun jae in hello my twenties?
Disambiguated questions and answers: question: Who plays adult Eun Jae in hello my twenties series 1?
Who plays young Eun Jae in hello my twenties series 1?
Who plays Eun Jae in hello my twenties series 2?
answer: Park Hye-su
Lee Na-yoon
Ji Woo
Natural Questions answer: Park Hye - soo (from the Wikipedia article "Hello, My Twenties!")