(written from a Production point of view)
Harney acted in the 1996 telefilm Gone in the Night with Holmes R. Osborne. A year later, Harney appeared in the airline thriller Turbulence (with Ben Cross, Catherine Hicks, and Scott Lawrence); also in 1997 was the telefilm Night Man (with DS9 recurring performer Felecia M. Bell) and Total Security (with Kristin Bauer and Tony Plana). At the end of the 1990s, Harney appeared in the film Sonic Impact (with Sam Anderson). In 1999, Harney was cast in the period film The 60s (with Bill Smitrovich and Clay Wilcox). He also worked in the telefilm Millennium Man (with Jonathan Banks, Jennifer Gatti, and Monte Markham). 2001 found Harney in the TV movie western Warden of Red Rock (with Jim Beaver and Mark Metcalf). Harney re-teamed with Michael Dorn in Shade(2003). In 2007, Harney got work in the Las Vegas Casino heist film Oceans Thirteen (with Ivar Brogger, movie performer Tommy Hinkley, and Wayne Péré, Scott L. Schwartz, and Ray Xifo). Finally, 2008 saw Harney in The Onion Movie (with Len Cariou, Scott Klace, and Don McManus).
Harney's first television appearance was a guest role on the legal drama L.A. Law (starring Corbin Bernsen and Larry Drake) in the episode "Whose San Andreas Fault is it Anyway?" (1994). Harney first worked with Scott Lawrence in the short-lived legal sitcom, The Great Defender (starring Richard Kiley) in the episode "12 Angry Men" (1995). That same year, Harney worked in the science-fiction series Space: Above and Beyond in the episode "Eyes" (with Lanei Chapman, Robin Curtis, Mark Lentry, and Tucker Smallwood). In 1996, Harney appeared on The Burning Zone (starring Jeffrey Dean Morgan) in the episode "Night Flight". Harney guested as Assistant District Attorney Frazier on The Practice in the episode "Trial and Error" (1997, with Robin Gammell, Willie Garson, James Greene, Natalia Nogulich, and Craig Wasson). Harney followed with Diagnosis Marder in the episode "The Murder of Mark Sloan" (with Mary Kay Adams). Harney also worked on the extraterrestrial drama The Visitor in the episode "Caged" (with Richard Cox and Bruce French).
Harney may be best known for his recurring role as the shady ex-detective Mike Roberts on NYPD Blue (along with Sharon Lawrence, Gordon Clapp, Michael Buchman Silver, Daniel Benzali, and Todd Waring).
Following his DS9 work in 1999, Harney first guested on Vengeance Unlimited in the episode "Justice" (with Katy Boyer, Mark Kiely, Rick Pasqualone, and Cliff Potts). Next was the time-travel series Seven Days (starring Alan Scarfe) in the episode "Parkergeist" (with Henri Lubatti). He appeared on ER in the episode "Last Rites" (with Cress Williams) and on Cold Case in the episode "Volunteers" (with Chris Sarandon and Karen Austin). He has also appeared on Weeds (with Andy Milder).