She was also Olivier-nominated for The Beggar's Opera (1982), The Wizard of Oz (1988), Uncle Vanya (1988), Guys and Dolls (1997), Entertaining Mr Sloane (2010), Good People (2015), and Follies (2018).

She later gained a wider audience for her role as Dolores Umbridge in the Harry Potter films The Order of the Phoenix (2007) and The Deathly Hallows - Part 1 (2010).

She also acted in Nanny McPhee, Another Year (2010), Pride (2014), and Downton Abbey (2019), and provide voiced roles in Chicken Run (2000), Arthur Christmas (2011), and Paddington (2014).

[14] She also appeared in two revivals of Guys and Dolls at the National Theatre; the first in 1982 in which she met her husband Jim Carter[15] and the second in 1996 in which she played Miss Adelaide and was nominated for the Olivier Award for Best Actress in a Musical.

[16] In 1985, Staunton won her first Laurence Olivier Award for Best Performance in a Supporting Role for her work in both The Corn Is Green at The Old Vic and A Chorus of Disapproval at the National Theatre.

[17] She also played Dorothy Gale in the Royal Shakespeare Company's 1987 revival of The Wizard of Oz at the Barbican Centre,[18][19] which earned her another Olivier nomination for Best Actress in a Musical.

[20] Staunton won her first Laurence Olivier Award for Best Actress in a Musical for playing the Baker's Wife in the original London production of Into the Woods (1990).

She also appeared in two productions at the Almeida Theatre, firstly in the premiere of Frank McGuinness's There Came a Gypsy Riding in 2007 and secondly in a revival of Edward Albee's A Delicate Balance in 2011.

Staunton performed the role of Sally in the 2017 National Theatre revival of Stephen Sondheim's Follies, alongside Janie Dee as Phyllis, and Philip Quast as Ben.

Other film roles include performances in Much Ado About Nothing (1993), Deadly Advice (1993), Sense and Sensibility (1995) Twelfth Night (1996), Chicken Run (2000), Another Life (2001), Bright Young Things (2003), Nanny McPhee (2005), Freedom Writers (2007) and How About You (2007).

Other film roles include the 2008 movie A Bunch of Amateurs, in which she starred alongside Burt Reynolds, Derek Jacobi and Samantha Bond, and the character of Sonia Teichberg in Ang Lee's Taking Woodstock (2009).

Staunton provided the voice of the Talking Flowers in Tim Burton's Alice in Wonderland (2010), and played one of the lead roles in the ghost film The Awakening in 2011.

An August 2018 announcement revealed that Staunton would be among the new cast to join the original actors in Downton Abbey which started principal photography at about the same time.

Staunton also played the wife of Detective Burakov in the 1995 HBO movie, Citizen X, which recounted the pursuit and capture of Russian serial killer Andrei Chikatilo.

In 2011, she was the Voice of the Interface in the highly acclaimed and nominee for the Hugo Award for Best Dramatic Presentation (Short Form) episode of Doctor Who – "The Girl Who Waited".

In 2012, she portrayed Alma Reville, the wife of Alfred Hitchcock, in the HBO television movie The Girl, which also starred Toby Jones and Sienna Miller.