(written from a Production point of view)
Shay Duffin (26 February 1931 – 23 April 2010; age 79) was the Irish actor and playwright who played Ned Quint in the Star Trek: The Next Generation seventh season episode "Sub Rosa" in 1993. He was born in Dublin, Ireland. He died from complications related to heart surgery at UCLA Medical Center in Los Angeles, California. He was 79 years old. 
Duffin regularly portrayed barkeep types, including the pubkeeper in the 1997 blockbuster Titanic and the brasserie bartender in the acclaimed 2006 crime film The Departed. He was perhaps best known for his role as Dan O'Grady in the 1993 horror film Leprechaun. Duffin was also known for his one-man plays, including The Importance of Being Irish in the early 1990s (which he also wrote) and Confessions of an Irish Rebel in 2006.
Duffin made his television debut in the NBC movie Law and Order, which was directed by Marvin Chomsky. Teri Garr, and James Whitmore, Jr. also had roles in this movie. Later that year, Duffin appeared in an episode of the CBS television series Switch, along with Richard Lynch and George Murdock.
He appeared in several more TV movies in the 1970s. He had a supporting role in 1978's The Other Side of Hell, which also featured Richard Riehle and Morgan Woodward. This movie was co-written by Robert Hamner and its music was composed by Leonard Rosenman. Duffin also played Rabbi Bartholomew in 1979's Mary and Joseph: A Story of Faith, which co-starred Stephen McHattie. Duffin's other TV movies during the 1970s included The Amazing Howard Hughes (with Barry Atwater, Ray Buktenica, and Garry Walberg), Captains Courageous (with Jeff Corey, Charles Dierkop, Ricardo Montalban, and Fritz Weaver), and Marciano (with Barbara Baldavin, Richard Carlyle, Richard Herd, and Michael Pataki).
In addition to Star Trek: The Next Generation, Duffin appeared on such TV programs as Dynasty (with Lee Bergere), Cagney & Lacey (in an episode with Stanley Kamel and Don Stark), and Murder, She Wrote (in an episode with George Hearn, Dakin Matthews, and Richard Riehle). He also had a role in the 1987 biographical TV movie J. Edgar Hoover, as did Walker Edmiston, Louise Fletcher, Robert Harper, Paul Kent, John McLiam, David Ogden Stiers, and Harvey Vernon.
Duffin was a regular cast member on the short-lived 1990 series City, created by acclaimed writer Paul Haggis. Fellow TNG guest star Stephen Lee was also a regular on this series. Duffin later had a recurring role on another CBS series from Haggis, Due South, in 1995.
Duffin's first feature film was the 1977 western The White Buffalo, in which Ed Lauter also appeared. Duffin was then one of the many Star Trek alumni to appear in the 1979 film Butch and Sundance: The Early Days; his co-stars in this production included Peter Brocco, Jeff Corey, Christopher Lloyd, John Schuck, Vincent Schiavelli, Peter Weller, and Noble Willingham. That same year, Duffin was seen in the boxing film The Main Event (with Earl Boen and James Gregory) and the western comedy The Frisco Kid (with Clyde Kusatsu, Vincent Schiavelli, and Ian Wolfe). Duffin was also seen in the 1978 short film Mother, Juggs & Speed with Jan Shutan.
Duffin played a ring announcer in the acclaimed 1980 boxing film Raging Bull with a young McKenzie Westmore as Jake LaMotta's daughter. That film's director, Martin Scorsese, later cast Duffin as the brasserie bartender in 2006's The Departed. The latter film's cast also included Mark Rolston. Duffin's only other film credits in the 1980s were the 1980 comedy The Baltimore Bullet (which also featured Ed Bakey) and the 1983 action thriller 10 to Midnight.
In 1992, Duffin had roles in the films Memoirs of an Invisible Man (with Sam Anderson, Rosalind Chao, Ellen Albertini Dow, Aaron Lustig, and Michael McKean), Newsies (with Gabriel Damon and Kevin Tighe), and The Public Eye (with Ian Abercrombie, Bob Gunton, Richard Riehle, and Nick Tate). In 1993's Leprechaun, Duffin plays Don O'Grady, the character who locks the title character away and steals his bag of gold coins at the beginning of the film. The film's cast also included Mark Holton and Ken Olandt.
Six years after appearing as the pubkeeper in Titanic, Duffin had a supporting role in the 2003 drama Seabiscuit. Both of these films co-starred Michael Ensign. Titanic featured Greg Ellis, Victor Garber, Tricia O'Neil, and David Warner, as well, while David Doty, Ed Lauter, and Michael Buchman Silver were also seen in Seabiscuit. Duffin's last film was 2007's Beowulf, which also co-starred Greg Ellis and Star Trek: Enterprise regular Dominic Keating.