(written from a Production point of view)
Timothy Olyphant (born 20 May 1968; age 47) is an actor who was in talks for an unspecified role in 2009's Star Trek, but both he and director/producer J.J. Abrams decided against it.  However, despite not being cast, Olyphant was allowed to guest-conduct the orchestra for a brief time during the film's scoring session. 
Olyphant is best known for his role as Sheriff Seth Bullock on the HBO series Deadwood, opposite the likes of Jim Beaver, Keith Carradine, Brad Dourif, Pasha Lychnikoff, and Paula Malcomson. He had supporting roles in such films as Scream 2, Go, Gone in Sixty Seconds, Dreamcatcher, A Man Apart (with Jeff Kober), and The Girl Next Door. For 2007, he played the male lead in the comedy Catch and Release, the villain in the action hit Live Free or Die Hard (co-starring Tim Russ), and the title role in the video game-based Hitman.
Olyphant is currently appearing as Wes Krulik on the FX series Damages. He has a number of films in the works, as well, including A Perfect Getaway with Chris Hemsworth.