Blake was born in Highgate, London to David and Molly Blake. Her mother was an illustrator and children's television presenter.^[2]

Blake regularly appeared in Victoria Wood's television programmes and has extensive radio credits. She appeared in the first episode of the sitcom One Foot in the Grave in which her character was responsible for firing Victor Meldrew, thus setting the events of the show in motion. She appeared as Bev Unwin in the ITV soap opera Coronation Street until her departure in December 2006.

Blake played the character of Madame Morrible in the West End production of Wicked, replacing Miriam Margolyes on 2 April 2007.^[3] Her final performance was on 12 April 2008 before she was succeeded by Harriet Thorpe.^[4] Blake appeared as a witch in the pantomime Wizard of Oz at The Lowry Theatre and Gallery, Salford, in 2004/2005.

In late 2008 to early 2009, she starred in the national UK tour of Boeing Boeing, and appeared as Judith in an episode of the third series of Wild at Heart. She was also in a national tour of Grumpy Old Women 2 in 2009 with Jenny Eclair and Wendi Peters.

Blake appeared as Hilary Nicholson in the RTÉ and BBC comedy Mrs. Brown's Boys, replacing Sorcha Cusack, who played Hilary in the first series. In 2015, she played The Queen in a theatre tour of the West End hit Handbagged.

Blake briefly reprised her Coronation Street role of Bev Unwin in July 2015 to help the long-running character Deirdre Barlow (played by Anne Kirkbride, who had recently died) bow out of the soap in January 2015.

In March 2019, Blake portrayed Agatha Christie's Miss Marple in a theatre production of The Mirror Crack'd at the Salisbury Playhouse.^[5] Then from 2023 to 2024, she will appear in a touring production of Murder in the Dark.^[6]

• Rooms, as Sarah (1974)
• Zodiac, as Peggy (1974)
• Armchair Thriller: A Dog's Ransom, as Marion Dowell (1978)
• Cribb, as Lotte (1979)
• Russ Abbot Madhouse (1981–1985)
• Victoria Wood: As Seen on TV (1985–1987)
• Something for the Weekend (1989)
• One Foot in the Grave, as Victor Meldrew's boss (1990)
• Darling Buds of May, as Mrs. Jerebohm (1991)
• The Wail of the Banshee, as Faye Morgan (1992)
• Mud, as Miss Dudderidge (1994–1995)
• Sooty's Amazing Adventures, as all the females (apart from Katarina) (1997–1998)
• A Prince Among Men, as Beverly (1997–1998)
• Roger Roger, as Eve (1999)
• The Quiet Garden, as Mother (2002)
• Coronation Street, as Bev Unwin (2003–2006, 2015; 373 episodes)
• Kelly & Lewis, as Carol Taylour (2007–2009)
• Wild at Heart, as Judith (2008)
• Murder Most Foul, as Elizabeth Bailey (2008–2009, 2013)
• Mrs. Brown's Boys, as Hilary Nicholson (2011–2013, 2015, 2017–present)
• Parents, as Alma Miller (2012)
• Great Night Out, as Mrs. B (2013)
• You, Me & Them, as Emma Grey (2013–2015)
• Cuckoo, as Belinda (2016)
• Murder on the Blackpool Express, as Marjorie (2017)
• Casualty, as Belle Radnor (2019)
• The Real Marigold Hotel, as herself (2020)^[7]
• Not Going Out, as Carol (2021)
• Kate & Koji, as Joyce (2022)

• Star Terk Two (1985/1986)
• The Phenomenon Squad (1987)
• Barrymore Plus Four (1995)
• Auntie's Secret Box (1996)

• The Mirror Crack'd at the Salisbury Playhouse (2019)
• Murder in the Dark across the UK and Ireland (2023)

• Susie Blake at IMDb