(written from a Production point of view)
Eric Robert Greitens (born 10 April 1974) is a former United States Navy SEAL and founder of The Mission Continues charity for post-9/11 veterans. He had a role in Star Trek Into Darkness as a Starfleet ceremonial guard.
Greitens was commended with the Purple Heart after surviving a suicide bombing in Fallujah. He returned to duty in 72 hours, but also set up The Mission Continues with his combat pay, along with the disability checks from two friends.
J.J. Abrams and his wife Katie McGrath contacted Greitens to partner with him.  As well as casting veterans in Star Trek Into Darkness, Greitens and Abrams have collaborated in other ways, such as conducting a survey that revealed common misconceptions about veterans, and distributing food to vulnerable children in Los Angeles. (Empire May 2013, p. 91)