Joo Won as Cha Yoo Jin (Piano/Violin/Conducting)
– Choi Kwon Soo as Yoo Jin (child)
Shim Eun Kyung as Seol Nae Il (Piano)

People around Cha Yoo Jin

Lee Ah Hyun as Yang Sun Young (Yoo Jin’s mother)
Jung Bo Suk as Cha Dong Woo (Yoo Jin’s father)
Kim Yoo Mi as Chae Do Kyung (Vocal major)

A-Orchestra

Park Bo Gum as Lee Yoon Hoo (Cello)
Bae Min Jung as Jung Shi Won (violin)
Lee Joo Hyung as Goo Sun Jae (oboe)
Baek Seo Bin as Han Seung Oh (Conducting)
Ah Yun as Son Soo Ji (piano)
Jo Yoon Woo as Lee Jae Yong (Trumpet)

S-Orchestra

Go Kyung Pyo as Yoo Il Rak (Violin)
Min Do Hee as Choi Min Hee (Contrabass)
Jang Se Hyun as Ma Soo Min (Timpani, all percussion)
Jung Sung Ah as Lee Dan Ya (viola)

Others

Baek Yoon Shik as Franz von Stressman (famous conductor)
Lee Byung Joon as Do Gang Jae (piano professor)
Ye Ji Won as Song Mi Na (Director of Dean School Music/former pianist)
Ahn Kil Kang as Yoo Won Sang (restaurant owner/Il Rak’s father)
Nam Goong Yun as Ahn Gun Sung (4piano professor)
Bang Eun Hee as So Ri Mo
Han Min as Jang Woo Sung
Moon Hee Kyung as Nae Il’s ex-teacher