- Donnie Yen
- Henry Chen
- Joe Chen
- Miss Liang
- Ming-Kit Lok
- Jack Li
- Kang Yu
- Kane Luo
- Bruce Kwan-Chi Tong
- Bruce Guan
- Chris Kwan-Yiu Tong
- Chris Guan
- Gladys Li
- Gladys Wang
- Chiu-Kin Lau
- Gordon Xiang
- Ka-Wah Lam
- Patrick Lin
- Alfred Cheung
- Chief Huang
- Fung Woo
- Fang Shu Ren
- Ying-Kwan Lok
- Guan's father
- Wai-Ho Auyeung
- Ben Sir
- Billy Lau
- Gladys's father
- Fung Lee
- Jack's grandmother
- Tin-Lung Koo
- Boss Zhang
- Qianqian Yun
- Jenn Zhou
- Andrew Sit-Chun Tse
- Jake Huang
- Qiunan Lin
- Young Henry Chen
- Zhi Wen
- Young Kane Luo
- German Cheung
- Big Wei
- Alan Choi
- Deng Bo
- Roger Budhrani
- Gordon's father
- Jess Liaudin
- MMA champion
- Semiquaver Iafeta
- Assistant boxer trainer
- Mike Leeder
- MMA champion's manager
- Tom Caserto
- Assistant boxer trainer
- Craig Miller
- Assistant boxer trainer
- Brahim Chab
- Assistant boxer trainer
- Jai Day
- Henry's Step Father
- Lockhart Ogilvie
- Assistant boxer trainer
- Harry Oram
- Fighter Harry'O
- Lee-Po Chan
- 6B student
- Sabrina Cheung
- 6B student
- Chung-Hang Leung
- 6B student
- Jeffrey Ngai
- 6B student
- Tsz-Tung Tam
- 6B student
- Kiu Tang
- 6B Student
- Jun Lam 'Toby' Wong
- Kane's thug
- Man Shing Wong
- Kane's dad
- David Johnson Wood
- US Marine
