The “small ceremony” took place on Saturday afternoon, a Downing Street spokesman said.
The spokesman added that the couple will celebrate again with family and friends next summer.
The stealth affair, described by PA Media as a “secret wedding,” was reportedly held in front of close friends and family, according to several British newspaper accounts.
“Many congratulations to @BorisJohnson and @carriesymonds & big love to Wilf. So many weddings have been delayed and disrupted by covid. Life is always better with love,” Ford wrote.
Later in 2020, she made her first joint television appearance with Johnson to thank NHS workers for treating him in hospital and delivering their baby.
The marriage comes just days after the couple were said to have sent save-the-date cards to family and friends for an event on July 30, 2022.
At age 29, Symonds became the youngest-ever director of communications at the Conservative Party. Analysts say she was crucial in tidying up Johnson’s famously disheveled persona during the leadership campaign.