| Name | Character | Episodes |
|---|---|---|
| Anna Cathcart | Katherine 'Kitty' Song Covey | 18 |
| Anthony Keyvan | Quincy 'Q' Shabazian | 18 |
| Peter Thurnwald | Alex | 18 |
| Jocelyn Shelfo | Madison | 16 |
| Michael K. Lee | Professor Lee | 13 |
| Yunjin Kim | Jina | 9 |
| Lee Sung-wook | Mr. Kim | 9 |
| Théo Augier | Florian | 8 |
| John Corbett | Dan Covey | 2 |
| Han Chae-young | Dami | 2 |
| Noah Centineo | Peter Kavinsky | 1 |
| Sarayu Blue | Trina | 1 |
| Ok Taec-yeon | Ocean Park | 1 |
| Janel Parrish | Margot Song Covey | 1 |
| Jenny Han | Check-In Lady | 1 |