The Metropolitan Police said officers were initially called after a large group blocked traffic before the situation escalated, with bottles thrown and fireworks set off. Riot police were deployed as clashes broke out, with videos on social media showing officers facing crowds amid smoke, flares and debris.
Police said one officer was taken to hospital with a head injury after it is believed he was struck by a glass bottle. He has since been released.
"One officer has been injured, and four people have been arrested following disorder in Edgware Road," a Metropolitan Police spokesperson said.
"Officers were initially called after a group of people congregated in the road and blocked traffic. The incident then escalated with the group throwing bottles and setting off fireworks.
"One officer was taken to hospital for head injuries; it is believed he had been hit by a glass bottle. He has now been released from hospital and no other injuries were reported. Officers remained in the area and made four arrests for violent disorder.
"We will not tolerate such disorder on our streets, or attacks on our officers. We will be reviewing CCTV and video footage circulating on social media to ensure all those responsible are brought to justice."
The unrest followed France's quarterfinal victory over Morocco in Boston, where second-half goals from Kylian Mbappe and Ousmane Dembele secured a third consecutive World Cup semifinal for the defending champions.
While scenes in London turned violent, celebrations in Paris were largely peaceful despite fears of unrest. Elsewhere in France, celebrations turned tragic when a 17-year-old girl died after falling from a truck in Aulnoye-Aymeries near Maubeuge. The driver was detained.
France's victory ended Africa's interest in the tournament, although Morocco became the first African nation to reach the World Cup quarterfinals on more than one occasion. Mbappe's eighth goal of the tournament also drew him level with Lionel Messi in the Golden Boot race.