Holm emerged as a solid film presence in his feature debut as an Irish gunner in "The Bofors Gun" (1968), earning a British Film Academy Award for Best Supporting Actor. He then crossed the Atlantic to star alongside fellow British actors Alan Bates, Dirk Bogarde, and David Warner in American director John Frankenheimer's "The Fixer" (1968), adapted from the novel by Saul Bellow. Holm also reprised his Tony-winning part for Peter Hall's feature version of "The Homecoming" (1973). Although his short, stocky stature had not prevented him from landing leading roles at the RSC, Holm found himself typecast as a character actor for the screen, though he continued to build a reputation for versatility and reliability. Most of his early film work was for British directors like Richard Attenborough ("Oh! What a Lovely War" 1969, "Young Winston" 1972) and Richard Lester ("Juggernaut" 1974, "Robin and Marian" 1976) or in period fare ("Mary Queen of Scots" 1971, "Nicholas and Alexandra" 1972). It took his role as Ash, the calculating robot, in fellow Brit Ridley Scott's "Alien" (1979) to raise his profile in Hollywood.
Holm earned a Best Supporting Actor Oscar nomination for his dedicated track coach in Hugh Hudson's "Chariots of Fire" (1981), the same year he played a comically mean-spirited Napoleon in Terry Gilliam's "Time Bandits". The actor later rejoined both directors, portraying the magnanimous Belgian explorer who rescues and educates a half-savage boy in Hudson's "Greystoke: The Legend of Tarzan, Lord of the Apes" (1984) and a blandly evil bureaucrat in Gilliam's "Brazil" (1985). After delivering a meticulous performance as the husband of a troubled woman (Gena Rowlands) in Woody Allen's "Another Woman" (1988), Holm returned to the comfortable world of Shakespeare in Kenneth Branagh's film version of "Henry V" (1989) and Mel Gibson's "Hamlet" (1990). After a turn as a jealous husband in David Cronenberg's "Naked Lunch" (1991), he rejoined Branagh for "Mary Shelley's Frankenstein" (1994), playing the father of the monster's creator. He also shined as the stern, unyielding, and slightly dotty physician who helps heal "The Madness of King George" (1994).
The small screen has afforded Holm some notable work, beginning with British projects like "The Body Snatcher" (1966) for Thames TV's "Mystery and Imagination" series and "Napoleon and Love" (Thames TV, 1974), in which he played the title character to Billie Whitelaw's Josephine. He made his American TV debut in a CBS special, "The Rebel" (1975), and, after roles in "Jesus of Nazareth" and "The Man in the Iron Mask" (both NBC, 1977), he played Nazi S.S. Chief Heinrich Himmler in the acclaimed NBC miniseries "Holocaust" (1978). The celebrated CBS remake of "All Quiet on the Western Front" (1979) cast him again as a German, as did the ABC miniseries "Inside the Third Reich" (1982, as Nazi propaganda chief Joseph Goebbels). He also turned up as Agatha Christie's famous sleuth Hercule Poirot in A&E's "Murder by the Book" (1990) and as Michelangelo's patron Lorenzo de Medici in "A Season of Giants" (TNT, 1991). Additionally, he starred as Pod opposite wife Penelope Wilton's Homily in the BBC's "The Borrowers" (1992), two six-part series based on Brit author Mary Norton's children's novels about a family of little people who live under the floorboards of an English country home that aired as "The Borrowers" (1993) and "The Return of the Borrowers" (1996) in the USA on TNT.
Despite his reputation as a prodigious worker, nothing in his film career had prepared Holm for the embarrassment of riches that followed his delicious portrayal of the rival restaurateur who ruins Stanley Tucci and Tony Shalhoub by promising and not delivering Louis Prima "Big Night" (1996). In 1997, he acted in four features, beginning with his role as a monk in Luc Besson's futuristic "The Fifth Element". He appeared as the tormented NYC cop father of Andy Garcia—who recommended Holm to the director—in Sidney Lumet's fourth installment of his continuing examination of corruption, "Night Falls on Manhattan", impressing local New Yorkers with his authentic Queens dialect. In Danny Boyle's "A Life Less Ordinary", Holm played the wealthy owner of a company whose daughter (Cameron Diaz) is kidnapped by the janitor (Ewan McGregor). The gem of this banner year was Atom Egoyan's "The Sweet Hereafter". Holm played with bottomless subtlety a big-city lawyer who arrives in a small town devastated by a fatal school bus accident, hoping to pursue some sense of justice in the face of his own personal tragedy. Egoyan, obsessed with Holm's compelling performance in "The Homecoming", cast him as the attorney, even though he was nearly the physical opposite of the character described in Russell Banks' heartbreaking novel.
Holm experienced stage fright so debilitating during previews for a 1976 production of Eugene O'Neill's "The Iceman Cometh" that, with the exception of a 1979 revival of "The Cherry Orchard", he did not return to the theater until Harold Pinter wrote "Moonlight" especially for him. After that 1993 production came off without a hitch, he felt emboldened enough to answer the call when friend Richard Eyre asked him to perform "King Lear" in 1997. Holm was the sensation of the London season in what he regards as his greatest achievement. Fortunately audiences can savor his work as he recreated his ferocious Olivier Award-winning portrayal for TV (airing on PBS in 1998), a performance which garnered an Emmy nomination (although he lost the award to friend Tucci).
After his hilarious turn as a heavily-accented scientist in Cronenberg's "eXistenZ" (1999), he took on the title role of Tucci's "Joe Gould's Secret" (2000), emphasizing the lucidity of his eccentric, homeless hobo and downplaying his alcoholism and obnoxious extremes. He also appeared that year in HBO's "The Last of the Blonde Bombshells" (earning an Emmy nomination for his work opposite Judi Dench), "Beautiful Joe" and "The Match." A frequent narrator of TV documentaries, Holm lent his voice to TNT's "Animal Farm" (1999, as Squeeler) and to ABC's animated "The Miracle Maker" (2000, as Pontius Pilate). After turns as Napoleon in "The Emperor's New Clothes" and as royal physician Sir William Gull in "From Hell" (both 2001), the actor undertook what perhaps will be one of his best-known roles, playing hobbit Bilbo Baggins in "Lord of the Rings: The Fellowship of the Ring" (2001) and "Lord of the Rings: The Return of the King" (2003), adapted from J.R.R. Tolkien's trilogy.
Holm next had a supporting role as a thoughtful climatologist in "The Day After Tomorrow" (2004), director Roland Emmerich's disaster film about the onslaught of a new ice age. He then gave a finely etched turn as a punishing psychiatrist father in writer-director-star Zach Braff's winning indie comedy-drama "Garden State" (2004). Also in 2004, Holm played the befuddled Professor Fitz in “The Aviator”, Martin Scorsese’s epic biography about maverick airline tycoon Howard Hughes—a serious contender for a few nods come Oscar time.