Her roles on television have included playing Leela in Doctor Who (1977–1978), Anne Reynolds in The Omega Factor (1979), Blanche Simmons in Tenko (1981–1982), Susan Young in Bergerac (1985–1990), Rosa di Marco in EastEnders (1998–2000) and Mary Goskirk in Emmerdale (2022–present).

Her early TV career highlights include appearances on Emmerdale Farm in 1973 as Sharon Crossthwaite, the first character in the soap to be murdered, and roles in Z-Cars and the television film The Game in 1977.

Jameson's inspirations for the way that she played the character included her dog, for "her instinctive nature and tendency to slightly cock her head when she perceives something", and a neighbour's child, for "openness and naïveté".

[1] Valerie Estelle Frankel, in her book on Women in Doctor Who, characterises Leela as "a classic warrior woman" but says that the seriousness of the character is undermined because "her provocatively cut hunting leathers and cleavage are offered to the male gaze in every episode.

"[7] Patrick Mulkern of Radio Times also regarded her as "a companion to lure in adolescent lads and their dads" but, while considering her debut serial to be a "lifeless tale", he wrote that Jameson was "a wonderful find.

Exuding commitment and conviction, she makes Leela earnest, warm and funny, elevating her far beyond Robert Holmes's desire for a 'Raquel Welch in the jungle'.

In 1998, Jameson began a long run in the BBC soap EastEnders as Rosa di Marco, appearing in over 200 episodes over two and a half years until August 2000.

In 2013, she starred in the play Gutted by Rikki Beadle-Blair and was nominated for Best Female Performance at the 2013 Off West End Theatre Awards (Offies).