(written from a Production point of view)
Mensah was born in Ghana, to parents of the Asante tribe but he moved to Hertfordshire, England with his father, an engineer, and his mother, a writer and two younger sisters at a young age. Deciding he wanted to experience more of the world, he eventually emigrated to Canada, where he did some television work, including an episode of Gene Roddenberry's Earth: Final Conflict, among other shows. He has also appeared in a number of Nero Wolfe mysteries with Bill Smitrovich and Saul Rubinek and appeared as General Perry in two episodes of the Fox television series Terminator: The Sarah Connor Chronicles, starring Thomas Dekker, in 2008.
In addition to his television work, Mensah has appeared in some films, most notably the science fiction thriller Avatar (2009), directed by James Cameron and starring Zoë Saldana from J.J. Abrams' Star Trek. The film, released in December 2009, utilized the virtual production studio developed by veteran Trek effects supervisor Robert Legato.
Other films include Bless the Child (2000), Harvard Man (2001), Jason X (2001), Triggermen (2002, with Saul Rubinek), Tears of the Sun (2003, with Fionnula Flanagan), and Hidalgo (2004, with Jeff Kober and Malcolm McDowell), He appeared in the popular 2007 film, 300, playing the unfortunate Persian messenger who gets kicked into the well by King Leonidas. The film also featured Stephen McHattie. In 2008, he played General Joe Greller in The Incredible Hulk, based on characters appearing in Marvel Comics magazines.
After the success of Avatar, Mensah went to star in the Starz series, Spartacus: Blood and Sand (renamed Spartacus: Vengeance), where he played Batiatus' doctore (trainer of gladiators) Oenomaeus.