(written from a Production point of view)
James Joseph Sloyan (born 24 February 1940; age 74) is the actor who portrayed several Star Trek characters over the span of three series. His largest, most frequent role is Mora Pol, the Bajoran scientist who first studied Odo, appearing in Star Trek: Deep Space Nine's second and fifth seasons.
One of Sloyan's earliest feature film credits was the 1973 classic The Sting. This film also featured the late Ray Walston, who later played Boothby on several episodes of Star Trek: The Next Generation and Star Trek: Voyager. He also played the role of Barnard "Barney" Smith in the 1979 Buck Rogers in the 25th Century two-parter episode "The Plot to Kill a City" (with Frank Gorshin, Felix Silla, Anthony James, Seamon Glass and Tim O'Connor). In 1970, he appeared in The Traveling Executioner with Graham Jarvis, Marianna Hill, Stefan Gierasch, Logan Ramsey, and James Greene.
Sloyan had a role in the 1978 mini-series Centennial. This series featured other Trek alumni, including Michael Ansara, Cliff DeYoung, Brian Keith, Sally Kellerman, Morgan Woodward, and Anthony Zerbe. He co-starred with Robert Picardo in the 1981 made-for-TV movie The Violation of Sarah McDavid and was also once a regular on the TV series Ryan's Hope, as was Kate Mulgrew. Sloyan's voice is familiar to many as he is the spokesperson for Lexus.
Sloyan made several appearances as Avery Baltus on the TV series Party of Five. He played Dr. Frank Nollette in The X-Files episode "Roland". He also guest starred in an episode of Quantum Leap, starring Scott Bakula, and appeared as Superintendent Hazen on several episodes of Dr. Quinn, Medicine Woman, starring Barbara Babcock.