(written from a Production point of view)
Danny Downey is a stuntman and stunt actor who was the stunt double for Kaj-Erik Eriksen in the Star Trek: Enterprise fourth season episode "Cold Station 12". He received no credit for his work. His costume was sold off on the It's A Wrap! sale and auction on eBay. 
Downey has doubled for stars such as Jeremy Davies, Elijah Wood, Rodney Eastman, Nick Wechsler, Ian Somerhalder, David Arquette, David Spade, Steve Buscemi, Tracey Walter, and Edward Furlong.
Among his stunt resume are films such as Nell (1994), Hackers (1995), Blood and Wine (1996), The Ice Storm (1997), Deep Impact (1998, with James Cromwell, Denise Crosby, Gary Werntz, Mark Moses, Tucker Smallwood, Ellen Bry, Concetta Tomei, Christopher Darga, and stunts by Tom Morga, Brian Avery, Joni Avery, Leigh Hennessy, Denney Pierce, and Mic Rodgers), Edtv (1999, with Clint Howard, Geoffrey Blake, Steve Kehela, Barry Wiggins, Cyndi Pass, Gina Hecht, Bob Sarlatte, and stunts by Anita Hart, Dana Hee, and Merritt Yohnka), House on Haunted Hill (1999, with Famke Janssen, Jeffrey Combs, and stunts by Rick Avery and Scott Leva), Pearl Harbor (2001), Jurassic Park III (2001, with Mark Harelik, Linda Park, Bruce French, and stunts by Bobby Burns, Lisa Hoyle, Wayne King, Jr., and Pat Romano), Planet of the Apes (2001), The Scorpion King (2002, starring The Rock), Freddy vs. Jason (2003), I Heart Huckabees (2004), Cursed (2005, with Michelle Krusiec, Derek Mears, and stunts by Joni Avery, Brian Avery, Alex Chansky, Paul Eliopoulos, Anita Hart, Buck McDancer, Angela Meryl, Chase Penny, and Boni Yanagisawa), Red Eye (2005), and Live Free or Die Hard (2007, with Tim Russ and stunts by Johnny Martin).
Downey has also performed stunts in television series such as Pacific Blue (1996), Oz (1998-1999), Charmed, CSI: Crime Scene Investigation, Roswell (starring William Sadler), V.I.P., 24 (2001), Boston Public (2002, starring Jeri Ryan), Angel, The Sopranos (2004), Gilmore Girls (2005), ER (2005), Without a Trace (2006, starring Enrique Murciano and stunt coordinated by Dennis Madalone), Bones (2006), CSI: New York (2006), and Zoey 101 (2005-2006).