(written from a Production point of view)
Leonard Kelly-Young (born 29 September 1948; age 66) is the actor from Chicago, Illinois who portrayed Sonsorra in the Star Trek: Enterprise first season episode "Cold Front" in 2001. His name is misspelled in the end credits of the episode as Leonard Keely-Young. His costume from this episode was later sold off on the It's A Wrap! sale and auction on eBay.  
Among his few other science fiction credits is the 1996 made-for-television movie Special Report: Journey to Mars, co-starring fellow Star Trek alumni Keith Carradine, Rosalind Chao, Deborah Lacey, and Alfre Woodard. His other TV movie credits include the TV movies No Place Like Home (1989, with Steve Rankin), The Enemy Within (1994, with Lawrence Pressman), Down, Out & Dangerous (1995, with Bruce Davison), Get to the Heart: The Barbara Mandrell Story (1997, with Dwight Schultz), Anarchy TV (1998, with Albert Hall, George Murdock and Matt Winston), When Billie Beat Bobby (2001, with Bob Gunton), and Taking Back Our Town (2001, with Keith Szarabajka). His feature film credits include 1992's There Goes the Neighborhood (in which he and Lee Arenberg played two burglars opposite Jonathan Banks, W. Morgan Sheppard, Ron Taylor and Harris Yulin), The Vanishing (1993, with George Hearn), Sliver (1993, with Jim Beaver), Ed (1996, with Bill Cobbs and Stan Ivar), Diamond Men (2000), and Karla (2006).
During the 1990s, he was a regular on the action series Renegade and had a brief stint on the soap opera Days of Our Lives. He has also made appearances on such series as Pros and Cons (starring Madge Sinclair), Beverly Hills, 90210 (with Ann Gillespie), Ellen, Married...with Children, Pacific Blue (starring David L. Lander), Silk Stalkings (with Charlie Brill and Zoe McLellan), Lois & Clark: The New Adventures of Superman (with Teri Hatcher and K Callan), CSI, That's Life (starring Scarlett Pomers, Paul Sorvino, and Titus Welliver), Six Feet Under (with Graham Jarvis), Carnivale (with Adrienne Barbeau, Clancy Brown, John Fleck, Scott MacDonald, Diane Salinger, and John Savage), and Boston Legal (with William Shatner, John Larroquette, David Clennon, Larry Drake, and Bruce Gray).