Miss Symonds is the daughter of the co-founder of The Independent Matthew Symonds, and one of the newspaper’s lawyers, Josephine Mcaffee.
She grew up in southwest London and went to the private Godolphin and Latymer School before she went on to study theatre studies and history of art at Warwick University.
She graduated from the esteemed university with a first class degree.
In 2009 Miss Symonds joined Conservative HQ as a press officer and went on to meet Mr Johnson in 2012 when she was working on his London mayor re-election campaign, and she then became director of communications at Conservative Campaign headquarters.
The PR expert also worked for Home Secretary Sajid Javid when he was in charge of local government and John Whittingdale when he was Culture Secretary.
In August 2018, she left the Conservative Party and started working in PR for Bloomberg for their Vibrant Oceans programme.
Mr Johnson and his wife Marina Wheeler released a statement in September 2018 saying they would be divorcing following 25 years of marriage.
The couple have four children together Lara Lettice, Milo Arthur, Cassia Peaches and Theodore Apollo.
Mr Johnson’s relationship with Miss Symonds became public following the announcement of his divorce and since then he has moved into her home in Camberwell, south London.
Mr Johnson is 55 making him 24 years older than his new partner.
Miss Symonds has been thrown into the limelight over the last few days as police were called to her flat, where Mr Johnson is now living, after neighbours were concerned for her welfare when they heard a blazing argument between the pair.
Neighbour Tom Penn has confirmed he called the police, saying in a statement: “My sole concern was the welfare and safety of my neighbours.”
The former Foreign Secretary was questioned over what happened at a Tory leadership hustings in Birmingham but he refused to answer any questions on the scandal.
Miss Symond’s ex boyfriend Oliver Haiste has spoken out to the Daily Mail about how “passionate” their relationship was.
He said: “We had quite a tumultuous relationship,
“I found when times were good with Carrie they were great – they were fantastic.”
“When times were bad they were awful. It was a highly passionate relationship. And I don't mean that in a salacious, physical sense. I mean in terms of emotional context – very emotionally charged.”
If Mr Johnson does beat Jeremy Hunt to becoming the next Prime Minister and he marries Miss Symonds while in the top job, he would be the fist serving Prime Minister to get married in 250 years.
It remains to be seen whether Miss Symonds will move into Number 10 with Mr Johnson and what role she will take on if she does.