Despite having different names in each movie, he played the same character in The Commitments (1991), The Snapper (1993) (TV) and The Van (1996).

Acted in the Focus Company in Dublin with Gabriel Byrne and Stephen Rea in the late 1970s.

Both he and his "Star Trek: Deep Space Nine" (1993) co-star Rene Auberjonois, appeared in "Stargate" series, each playing the leader of a human civilization on another planet whose population lived under the surface. In both cases, the main characters of the series in question attempted to form an alliance and arrange an exchange of technology before learning that this civilization could not be trusted. Meaney played Cowen, leader of the Genii in three episodes of "Stargate: Atlantis" (2004); Auberjonois played Alar, leader of the Eurondans, in one episode of "Stargate SG-1" (1997).

Along with Patrick Stewart and Armin Shimerman, he is one of only three actors to appear in the pilots of two different "Star Trek" series: "Star Trek: The Next Generation" (1987) and "Star Trek: Deep Space Nine" (1993) for Patrick and Colm. Armin appeared in "Star Trek: Deep Space Nine" (1993) and "Star Trek: Voyager" (1995).

His role and rank in the Star Trek series took several years to evolve. Beginning as a crewman in "Star Trek: The Next Generation" (1987) the character of Miles O'Brien then graduated to the transporter room and was briefly a lieutenant before being made a chief petty officer, thus joining one of the very few recurring enlisted roles in Star Trek (Mr Leslie and Yeoman Rand being two others from the original series). Transferring to "Star Trek: Deep Space Nine" (1993), the O'Brien character mutated the first two seasons between a warrant officer and an ensign junior grade before again becoming enlisted as a senior chief petty officer around the fourth season. In the last seasons of "Star Trek: Deep Space Nine" (1993), the rank of senior chief was once and for all confirmed and O'Brien became the first-ever Star Trek enlisted character to be given an enlisted rank insignia collar pin.

Is the only actor to appear in 14 different seasons of "Star Trek," more than any other actor ("Star Trek: The Next Generation" (1987), seasons 1 through 7, and "Star Trek: Deep Space Nine" (1993), seasons 1 through 7).

Along with Jonathan Frakes, Brent Spiner, Marina Sirtis, Michael Dorn, and Jeffrey Combs, he is one of only six actors to appear in the finales of two different "Star Trek" series: "Star Trek: The Next Generation" (1987) and "Star Trek: Deep Space Nine" (1993).

Was a background character on "Star Trek: The Next Generation" (1987)'s pilot episode, Encounter at Farpoint (1987). He had a semi-recurring role as "Battle Bridge Conn." His character was eventually given a name and rank (transporter chief Miles Edward O'Brien). He was made the engineer of DS9 on "Star Trek: Deep Space Nine" (1993) in 1993.

Former son-in-law of Irish-American actor Vincent Dowling and Brenda Doyle.

Played the same character, Chief Miles Edward O'Brien, on "Star Trek: The Next Generation" (1987) and "Star Trek: Deep Space Nine" (1993) for twelve consecutive years from 1987 to 1999. The only other "Star Trek" actor to do this is Michael Dorn.