[3] Chasen and her mother moved to the UK and she trained at the Royal Academy of Dramatic Art, where she acted on stage and went on tour with Frankie Howerd in Hotel Paradiso.

When I first joined it, for the first few months I was in, it was great fun but after Jack (the producer) went it became less good and less fun and I didn't enjoy it so much".In 2011, Chasen was cast as Lydia Simmonds, Janine Butcher (Charlie Brooks)'s maternal grandmother and Norman Simmonds' (George Layton) mother,[6] in the BBC soap opera EastEnders, after the original actress Margaret Tyzack had to pull out of the role for personal reasons.

[11] EastEnders' executive producer, Bryan Kirkwood, added: "In order to continue the current storyline we've taken the decision for Heather Chasen to take over the role of Lydia.

[4] She had guest roles in Z-Cars and Dixon of Dock Green[17] and voiced a number of characters in the radio show The Navy Lark, particularly WREN Heather Chasen and "battle axe" Ramona Povey.

[20] She played Sylvie Leigh in Holby City and, for five episodes, Madge Bennet in the Channel 5 soap opera, Family Affairs.

[1] Earlier credits include, playing "rich bitches" Caroline Kerr, in The Newcomers and Isabel Neal in Marked Personal, alongside Stephanie Beacham.

[21] Other than this, she appeared in Pardon Ma Prime Minister alongside Gerald Flood and Paul Curran, written by Edward Taylor and John Graham who created the BBC radio series The Men from the Ministry.

[18] Chasen opined that she had a "lovely time" playing Miss Marple in A Murder is Announced alongside Richard Todd and Barbara Murray.

[23] Chasen appeared alongside Marina Blake, Sergei Chonishvili, Ifan Huw Dafydd and ex-EastEnders actor Dudley Sutton.

[25] In Call Me Jacky, she played an alcoholic lesbian, and later claimed to have based her characterisation partly on the novelist and playwright Patricia Highsmith, whom she knew well.

[28] Chasen was nominated for the Tony Award for Best Performance by a Featured Actress in a Musical, while she appeared in the New York adaptation of A Severed Head between 1963–1965.