"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".
Kremlin spokesman Dmitri Peskov said that Moscow is hopeful of better relations following Theresa May's inauguration as Prime Minister.
The White House is pushing back on suggestions that her selection of Boris Johnson as foreign minister will be problematic for the U.S. Johnson had previously described Obama as a "part-Kenyan" who had an "ancestral dislike of the British empire". He says Obama is confident the US will keep working to strengthen relations "irrespective of specific personalities".
His appointment was met with dismay across Europe's political class, with French Foreign Minister Jean-Marc Ayrault accusing him of lying during the European Union referendum campaign.
Ayrault said people had seen what his style was like during the referendum campaign, adding that Johnson "lied a lot to the British". "Now, it's him with his back against the wall to defend his country and to clarify his relationship with Europe", Ayrault said.
US Secretary of State John Kerry called Johnson, and both "agreed that the US-UK special relationship is as essential as ever", said the State Department.
The U.S. -born, part-Turkish Johnson said Britain was quitting the European Union but "that does not mean in any sense leaving Europe".
When she was running for the Conservative leadership, May promised that "Brexit means Brexit", and her appointments of Johnson, Davis and arch-euroskeptic Trade Secretary Liam Fox signal to European Union leaders that, no matter what her own feelings, she will not be watering down Britain's commitment to leaving the EU. And I know because we're Great Britain.
The foreign policy spokesman for German Chancellor Angela Merkel's party in Parliament said Thursday that many current British suggestions for future relations with the European Union were "unworkable". Although he won't be leading the U.K.'s negotiations on withdrawal from the EU, he may have around two years, while Britain is still a member of the bloc, to participate in talks on European foreign policy.
Downing Street says Liz Truss has been named justice secretary and lord chancellor - the top official in the judicial system.
May came to power with a reputation for acting with careful calculation, but with her choice of the voluble, publicity-craving Johnson as Britain's representative on the world stage, she appears to have thrown her customary caution to the winds.
Justine Greening, formerly in charge of worldwide development, is now education secretary and minister for women and equalities.
Germany's Handelsblatt called Johnson a "political jester", the daily Sueddeutsche labelled his appointment an example of "British humor", while the French L'Obs news magazine's headline was simply "King of the Blunder".
But he was undercut by key ally (and campaign manager) Michael Gove, who pronounced Johnson unfit to serve and ran (with no success whatsoever) for party leader himself.
The French minister said he needs a negotiating partner who is "clear, credible and reliable" for the upcoming negotiations on Britain's stated desire to leave the 28-nation EU. German Finance Minister Wolfgang Schaeuble said Thursday: "We must let Her Majesty's new government have a bit of time to make the necessary decisions".
But he said that "it's also important to point out that the quicker we succeed in creating clarity, the better it is to limit possible risks".
New British Prime Minister Theresa May is clearing rivals from government as she assembles her new Cabinet team. The treachery left Johnson out of the Conservative leadership race.
By awarding such a senior job to Johnson, she also showed a conciliatory side.
"At this incredibly important time that will determine Britain's economic and cultural relations with Europe, it is extraordinary that the new prime minister has chosen someone whose career is built on making jokes", Farron said.
Juergen Hardt said in a statement Thursday that, for example, "free access to the common market means, among other things, accepting other fundamental freedoms such as the freedom of movement" between European countries.
Later in the day Thursday, Hammond is slated to meet with Bank of England governor Mark Carney to discuss the British economy moving forward.
Hammond offered calming tones to the markets and the public in a series of interviews the morning after taking office.
"The number one challenge is to stabilize the economy, send signals of confidence about the future, the plans we have for the future, to the markets, to businesses, to global investors", Hammond told Sky News.