Titmuss graduated from City University in St Bartholomew's Hospital in 1998. She did a nursing diploma, because she "was interested in becoming a Doctor, but hadn't taken A level Chemistry" and became a staff nurse at London's University College Hospital.

Titmuss first came to public attention as the girlfriend of TV presenter John Leslie whom she met in a Fulham bar on 10 April 1999. She also claimed in her memoir that she has had relationships with former footballer and reality television personality Lee Sharpe, whom she met on the ITV1 show Celebrity Love Island, and English actor, author and television presenter David Walliams. In 2017, she married Days Of Our Lives co-star Ari Welkom.

Titmuss started playing poker "seriously" around 2001. In 2008, Titmuss played in the charity, side-event "Ante Up For Africa" of the World Series of Poker, in Las Vegas. Ladbrokes Poker started sponsoring her in 2005, when she appeared in the first Ladbrokes Poker European Ladies Championship.

Titmuss was hired as a roving reporter on the Channel 4 programme Richard & Judy, in late 2003, and stated at the time that the job was "an absolute dream come true". She lost her job in January 2004 following allegations of group sex with her boyfriend John Leslie. A sex tape from four years earlier emerged, in which she had been privately filmed having sex with Leslie and aspiring female model Aisha Abubakar. The footage was downloaded without permission from a private computer and made public by "conman" Lanre Onabowale, subsequently convicted to serve 18 years in jail for four counts of rape.

In December 2004, Titmuss appeared on the front cover of FHM again, with Swedish model Victoria Silvstedt, "marking," as she wrote, "the first time a girl was on the FHM cover twice in one year."

In 2005, Titmuss produced a book, co-written with Jayne Lockwood, called Ten Fantasies, in which she reveals her "ten most secret sexual fantasies." She stated that she did not want her mother to read it.

In 2006, Titmuss had a small role in the film Goal! 2 and in 2007 appeared in the second series premiere of Rob Brydon's Annually Retentive, which aired on BBC Three and as a character called Gezebelle in an episode of Katy Brand's Big Ass Show, a Sketch comedy series for ITV2.

After announcing in late 2007 that she would take a break from her glamour modelling career to concentrate on acting, Titmuss returned with a Nuts shoot in April 2009 to promote one more calendar.

On 24 July 2008, her memoir, titled The Secret Diaries of Abigail Titmuss, on which she collaborated with Heat Journalist Lucie Cave, was published by Headline Review. It is written in the form of a diary and is a day-to-day summary of her life for the past six years. It includes an indepth look into the trial of Titmuss' then boyfriend, John Leslie, at the time when he had been accused of rape, her rise to fame and how she dealt with the tabloids invading her life.

From November until December 2009, Titmuss appeared in Shakespeare's Macbeth, playing the character of Lady Macbeth with the Seagull Rep. The production opened at the Seagull Theatre in Lowestoft before transferring to other East Anglian venues.

On 18 February 2012, she played the role of Tara Edmonds in an episode of BBC TV's Casualty. She said that landing the part gave her a sense of self-esteem that she had lost doing the glamour work.

In an article published by The Daily Mail in January 2015, Titmuss announced that she had changed her name to Abigail Evelyn, in the context of her relocation to Hollywood, California and her attempts to establish a new career as an Actress.