Pacula was born Ioana Pacula in Tomaszow Lubelski, Poland to a pharmacist mother and an engineer father. In 1979, Pacula graduated from The Theatre Academy in Warsaw and joined Warsaw Dramatic Theatre where she acted until 1981. She started her career playing in productions of Shakespeare's Romeo and Juliet, Othello and As You Like It. She also found work in a handful of films, including Krzysztof Zanussi's Barwy ochronne/Camouflage (1977).
In 1981, she was caught in Paris when communist authorities in Poland declared martial law. In 1982 Pacula eventually emigrated to the U.S. (probably as an asylee) where she has specialized in playing European temptresses since her feature debut opposite William Hurt in Gorky Park (1983). She played the part of the exotic beauty in numerous American TV series and movies, including the Holocaust drama "Escape From Sobibor" (CBS, 1987), "The Kiss" (1988), "E.A.R.T.H. Force" (CBS, 1990), and the TV series, "The Colony" (ABC, 1996).
Pacula was featured in "Marked for Death" (1990) as an expert on Jamaican voodoo and gangs; in the Italian erotic thriller "Husbands And Lovers" (1992) as a free spirited adultress (which featured a rather controversial bare-bottom spanking scene, a first in a mainstream film); "Tombstone" (1993) as Doc Holliday's lover, Kate (also known as Big Nose Kate and Mary Catherine Haroney, born November 7, 1850); in "The Haunted Sea" (1997); and in the movie "Virus" (1999), playing a Russian scientist. Currently she resides in Southern California.