The conservative member of parliament is believed to have received the offer from the country's new prime minister, Theresa May, largely because he was a prominent figure in the campaign for Britain to leave the European Union.
"He [Boris Johnson] was the face of the leave campaign, so it was sensible to have him as a high-profile colleague," Time Bale, politics professor at Queen Mary University London told ABC News, adding: "I think it was also a juicy enough portfolio he couldn't refuse but one in which he could implode without damaging the country."
While foreign policy might not be a priority for many British voters, leaders around the world have voiced their concern with this appointment.
Sweden’s former prime minister, Carl Bildt, took to Twitter, saying: "I wish it was a joke, but I fear it isn't. Exit upon exit."
The White House officially welcomed the appointment but a meeting with Obama could be awkward, considering Johnson described the president in a recent newspaper article as "part-Kenyan" and biased against Britain because of an "ancestral dislike of the British empire".
The lack of respect between Johnson and the U.S. seems to be reciprocal. Wikileaks re-published a cable sent in 2008 describing Johnson as “a mistake-prone former journalist twice exposed for committing adultery."
Having such undiplomatic character representing the country internationally is a "high risk," according to professor Bale.
"He is used to selling London and the U.K. abroad but he's going to have to act in a collegial manner in a number of cabinet committees," Bale said, adding that if there was a time for Johnson "to grow up," this was it. "
It could be the ultimate threat to his career, or the ultimate opportunity," Bale predicted.
Johnson was also poked at domestically. One member of parliament, Tom Brake, jokingly asked ministers to set out how U.K. manufacturers can help create "transcontinental zip wires to enable our new foreign secretary to travel cheaply and with low environmental impact and in the style he is accustomed to around the world," referring to the now-famous picture of him stuck on a zip wire.
At least one prominent figure has come out saying he's a fan of the new minister. Australia's former prime minister, Tony Abbott, tweeted a picture of him and Johnson, saying, "Good to see @BorisJohnson as the new UK foreign secretary. He's a good friend of Australia."
"It's inevitable there's going to be a certain amount of plaster coming off the ceiling," Johnson said in his first short press statement as foreign secretary today, adding he wanted "more Britain abroad" and a "greater global profile" following Brexit.