Ludi Lin is the only reoccurring actor on the show who regularly practices martial arts outside of his work.
Olivia Liang (actress for Nicky) purposely avoided learning martial arts before this role due to perceived stereotypes. Liang said in an Associated Press interview that she would only do martial arts unless she was paid to do so.
This series is based on an original series concept co-developed by Bruce Lee & Bill Krieger for a proposed TV series that ultimately was modified into Kung Fu (1972). According to Linda Lee Cadwell, Lee originated the concept, and was intended to star in the series, but David Carradine was cast because the network felt the American audience was not ready for an Asian actor as the lead, and Lee received no credit for his concept (this was dramatized in Dragon: The Bruce Lee Story (1993).
This is a reboot of the original 1972 TV series starring David Carradine, only with a female lead and taking place in present day.
The CW announced in Feb. 2020 that they cast actress Olivia Liang as the female lead.