Harrison Newman

Lieutenant Harrison Newman is a Starfleet officer who served as the chief of security of the USS Valentine, replacing Robert Carver who was killed in action. (Star Trek: The New Adventures)

He used to be the chief of security on the USS Aldrin until it was destroyed about a month before he transferred to the Valentine. But he was glad he was off the Aldrin, since he hated the senior staff. (TNA: "The Unexpected Child")

Background information
He was played by actor Matt Bomer.

He was one of the final candidates for the role, the others being Daniel Craig, Robert Downey, Jr. and Chris Hemsworth. However producer Ronald G. Hutson said that he didn't want a famous celebrity that he's heard of.

Bomer liked the role so he decided to audition, he got the part. (remember this isn't real)

In the original script, it was said that Newman was an orphan whose family was killed during a battle with Klingons, however the background story is still being developed.