(written from a Production point of view)
Casey was not a Star Trek fan when he was cast as Hudson. In a 1994 interview, he said "I did "The Maquis" because I wanted to work with Avery Brooks, whom I admire as an actor". Casey was impressed by Brooks' performances in Spenser for Hire and A Man Called Hawk and his theatre performances as Paul Robeson. 
Among his film work, Casey starred in the 1984 comedy hit Revenge of the Nerds with James Cromwell and Brian Tochi. He appeared in the movie Spies Like Us. He portrayed Admiral Vanalden in an episode of seaQuest 2032 entitled "Chains of Command" alongside Gary Bristow, where his adversary's name was also Hudson. He also played Bubba Haywood in Roots: The Next Generations (with Brock Peters, Percy Rodriguez, John Rubinstein, Bruce French, and Paul Winfield). Casey is also one of the only Star Trek actors to have played a major role in the James Bond film franchise, becoming the first African-American to play CIA agent Felix Leiter opposite Sean Connery in the unofficial Bond film, Never Say Never Again in 1983. He appeared in the 1980 miniseries, The Martian Chronicles, based on Ray Bradbury's book. The series also featured Fritz Weaver. Other credits include the 1990 action sequel Another 48 Hours, with Kevin Tighe, Ed O'Ross, David Anthony Marshall, Page Leong, Allan Graf, Biff Yeager, Rex Pierson, Benjamin W.S. Lum , Victor Brandt, Patricia Tallman, and Shauna O'Brien.
Before becoming an actor, Casey was a track and field champion and professional football player.  As a Screen Actors Guild member (since SAG-AFTRA), Casey worked in several positions for this union and was voted to serve as SAG National Board alternate and to the Hollywood Division Board of Directors. 
- Bernie Casey at Wikipedia
- Remembering DS9 Guest Star Bernie Casey, 1939-2017 at StarTrek.com, the official Star Trek website