Shea's first screen role in "It's My Turn" (1980) ended on the cutting room floor. He was seen to good effect as the son of Jack Lemmon who disappears in Costa-Gavras' "Missing" (1982), won a Best Actor citation at the Montreal Film Festival for his role in "Windy City" (1984) and delivered a villainous turn in "Honey, I Blew Up the Kid" (1992).
Shea is also a popular TV actor and won an Emmy for his performance in the 1988 "surrogate mother" miniseries, "Baby M." He co-starred in the short-lived CBS series "WIOU" (1990) and was featured during the run of "Lois & Clark: The New Adventures of Superman" (ABC, 1993-97) as the charmingly corrupt Lex Luthor.