Which actor played the recurring transporter chief Miles O'Brien on TNG?

Colm Meaney played the recurring transporter chief Miles O’Brien on The Next Generation.

Meaney first appeared in TNG’s 1987 premiere, “Encounter at Farpoint,” initially as an unnamed helm officer. The character returned in small roles before becoming the Enterprise-D’s transporter chief, and the production gradually established his name, background, and family life.

O’Brien’s responsibilities went beyond operating the transporter. He was a practical engineer and experienced Starfleet technician, and his working-class Irish identity distinguished him from the mostly commissioned officers around him. His rank and insignia were inconsistent during TNG, but he was eventually established as a senior chief petty officer.

In 1993, Meaney carried O’Brien into Star Trek: Deep Space Nine, where the character became chief of operations and later chief engineer of the USS Defiant. That move explains a common mix-up: Ethan Phillips played Neelix, René Auberjonois played Odo, and Robert Picardo played the Emergency Medical Hologram—not Miles O’Brien.