“Kevin!” With that panicked exclamation, delivered in wide-eyed, straight-to-camera close-up in the festive comedy Home Alone (1990), the actor Catherine O’Hara, who has died aged 71 after a short illness, cemented her place as one of cinema’s most neglectful screen parents.

After inadvertently leaving her young son (played by Macaulay Culkin) behind in Chicago at the mercy of burglars while the rest of the McCallister family flies to Paris for Christmas, O’Hara’s character, Kate, spends the film struggling to get back to him. On her return trip, she accepts a lift from a polka band. Its leader is played by John Candy, one of O’Hara’s stablemates – along with Martin Short, Eugene Levy and Gilda Radner – from her early days in Toronto’s improvisational comedy troupe Second City.

To misplace a child once may be regarded as a misfortune. To do so twice looks like carelessness. Then again, plausibility is no match for the pressure to repeat a $477m hit – and so it was that Kevin was again estranged from his family in Home Alone 2: Lost in New York (1992). O’Hara transformed maternal despair into frantic comedy once more.

The role brought her fame but was not typical of her work. Eccentrics suffused with vanity, mischief or vulnerability were much more O’Hara’s style.

Before Home Alone, she had found a wide audience in Tim Burton’s comedy Beetlejuice (1988). She played Delia Deetz, a pretentious sculptor who moves with her husband and stepdaughter into a creaky Connecticut house whose previous occupants – now ghosts – plot to evict them.

In the film’s standout sequence, the family and their dinner party guests are suddenly possessed and forced to sing and dance to Harry Belafonte’s calypso hit Day-O (the Banana Boat Song). As the first to be turned into a kind of human marionette, O’Hara’s blend of horror, embarrassment and slow-dawning rapture is a delirious slapstick joy. In her review of the film, the critic Pauline Kael singled out the actor’s “sexy evil eyes” and called her “the possessor of the freakiest blue-eyed stare since early Gene Wilder”. O’Hara returned as Delia in the sequel Beetlejuice Beetlejuice (2024), roaming the underworld after being fatally bitten by asps.

The most deranged of O’Hara’s creations, however, was Moira Rose in the popular sitcom Schitt’s Creek (2015-20). This grande dame, former soap star and woman of many wigs, each of them named, is reduced to sharing cramped rooms in an Ontario motel with her doting husband and two spoilt adult children after the family loses its fortune. Dreaming of recapturing her former opulence and status, she hitches her wagon to dubious projects including a horror sequel called The Crows Have Eyes 3: The Crowening and a commercial for ghastly fruit wine (“It tastes like amoxicillin”) in which an increasingly sozzled Moira mangles the vintner’s name in ever more tongue-twisted ways.

Instances of her cuckoo behaviour across the show’s six series were innumerable, her couture wardrobe incongruous in the folksy setting, her accent mystifyingly wayward: she might airily pronounce her son David’s name as “Dare-vid”, or render “baby” as “bare-bare”. For O’Hara, this verbal crazy-paving was part of the point. “When people try to imitate that character,” she said, “the mistake they make is to be consistent.” Still, Moira was rarely less than a loving mother. “What have I told you about putting your body on the internet?” she asks her daughter in one episode. “Never! Never without proper lighting.”

O’Hara won an Emmy and a Golden Globe for her performance in the series, which was co-written by Levy and his son, Dan Levy, who played her husband and son respectively. O’Hara and Eugene Levy, who briefly dated in their improv days, also sparked together magically in four astute and exceptionally funny films directed by Christopher Guest and co-written by him and Levy.

Waiting for Guffman (1996) concerns a Missouri am-dram society whose members believe that their new musical celebrating local history (there is a production number about the manufacture of foot-stools) has Broadway potential. In keeping with the film’s genial tone, O’Hara’s evident love for her character, a travel agent and atrocious actor, generates a warmth that precludes cruelty.

In Best in Show (2000), she and Levy play a married couple whose trip with their terrier to a dog show is beset with problems, beginning when a lack of funds sees them downgraded at their hotel from a suite to a broom cupboard.

They were a couple again, albeit estranged, in A Mighty Wind (2003), about a memorial concert of folk musicians. Reunited for the gig, their characters Mitch and Mickey provide the touching emotional undercurrent of this silly but painstakingly authentic film, before going their separate ways. O’Hara, as Mickey, is last seen performing a song about catheters at a medical supplies trade show.

For Your Consideration (2006) was the only one of her films with Guest not to adopt the mockumentary format, though it was no less hilarious for that. O’Hara is the humble veteran whose head is turned by rumours that she may receive an Oscar nomination for playing a dying matriarch in a modest indie drama. Soon, she is wearing red leather numbers and undergoing plastic surgery that fixes her mouth in a rictus grin. The part played to O’Hara’s speciality: the comedy of delusion.

While the structure and plot points of Guest’s films were committed to paper, the lion’s share of the material was improvised by the cast, and it was not unusual for the finished 90-minute product to have emerged from as many as 60 hours of raw footage.

“To me, the most rewarding improvising is having agreed on an idea beforehand, where the scene might go, who your character is, or what might possibly be funny about your character, and at the same time be completely open to the other people because you’re not alone,” O’Hara said.

In his book Improv Nation, Sam Wasson calls her “one of the most fluid improvisers of her generation. Others may be crazier; none were as elegantly at ease.”

She was born and raised in Toronto, the sixth of seven children. Her mother was an estate agent and her father worked for Canadian Pacific Railways. Their sense of humour, she said, informed hers. “My father told great jokes he brought home from the office and my mother imitated everybody. I like to think I’m a combination.”

She was educated at Burnhamthorpe Collegiate Institute, Toronto, and auditioned for the Second City company only to end up as a waitress. Eventually, she was appointed understudy for Radner, who was dating O’Hara’s brother. Explaining her initial approach to improv, O’Hara said: “My crutch was … when in doubt, play insane. Because you didn’t have to excuse anything that came out of your mouth. It didn’t have to make sense.”

Between 1976 and 1984, the sketch show SCTV, a television spin-off of Second City, became a cult success, earning O’Hara and her fellow writer-performers an Emmy in 1982.

In Martin Scorsese’s zippy black comedy After Hours (1985), she drove an ice-cream van through Manhattan as part of the nocturnal hunt for the film’s hero, a computer programmer falsely suspected of murder. She was a gossipy journalist in Heartburn (1986), directed by Mike Nichols and based on Nora Ephron’s semi-autobiographical novel about her marriage to the journalist Carl Bernstein. She was also in Warren Beatty’s comic-strip adventure Dick Tracy and Alan Alda’s comedy Betsy’s Wedding (both 1990).

Most recently, she was impressive in very different roles in two 2025 TV hits: as a former studio boss modelled on Sony’s Amy Pascal in Seth Rogen’s film-industry comedy The Studio, and in the second season of the zombie drama The Last of Us as therapist to the hero, played by Pedro Pascal.

O’Hara’s many voice performances included Chicken Little (2005), Spike Jonze’s live-action adaptation of Where the Wild Things Are (2009) and The Wild Robot (2024). She also provided voices in two stop-motion gothic animated films from the Burton stable: The Nightmare Before Christmas (1993), directed by Henry Selick, and Burton’s 2008 feature-length version of his own 1984 short Frankenweenie. Her various roles in the latter included “Weird Girl” – a fair description of the niche she carved for herself.

She is survived by her husband, the production designer Bo Welch, whom she met on the set of Beetlejuice and married in 1992, by their children, Matthew and Luke, and her six siblings, including the singer Mary Margaret O’Hara.

• Catherine Anne O’Hara, actor, born 4 March 1954; died 30 January 2026