Los Angeles and Paris were originally competing to host the 2024 Olympics. But the IOC approved a plan last month to name the hosts of both the 2024 and 2028 Games simultaneously, assuring that each city will be awarded an Olympics.
Under the terms of the 2028 host city contract, the IOC will advance $180 million to the organising committee of Los Angeles due to the longer planning period and to fund youth sports in the years leading up to the Games.
The 2020 Games will be held in Tokyo. Boston was the top American city vying for the Games until its bid collapsed two years ago over concerns about use of taxpayer cash.
"The IOC welcomes this decision of the Los Angeles Olympic and Paralympic bid committee. They presented a strong and enthusiastic candidature that embraces the Olympic Agenda 2020 sustainability priorities by incorporating existing facilities and encouraging the engagement of more youth in the Olympic Movement," IOC President Thomas Bach said.
"Therefore, we are very happy that as part of this host city contract, we are able to expand the impact of city youth sports programming and encourage the healthy lifestyle of Angelenos for the next 11 years.
"We are very confident that we can reach a tripartite agreement under the leadership of the IOC with LA and Paris in August, creating a win-win-win situation for all three partners," he added.
The plan to announce hosts for two Olympic editions simultaneously is meant to provide stability since the IOC has had trouble in recent years in attracting bids. Potential host cities have been wary of the high cost of organising the world's biggest sporting spectacle.
Russia spent a record $51 billion to host the 2014 Winter Games in Sochi, while organisers of the 2016 Summer Games in Rio de Janeiro have struggled to pay off debts.
When Beijing was selected to host for the 2022 Winter Games, the only other option was the Kazakhstan capital of Almaty after Oslo, Krakow, Stockholm, St. Moritz and the Ukrainian city of Lviv all backed out.
"This is a historic day for Los Angeles, for the United States and for the Olympic and Paralympic Movements around the world. Today, we take a major step toward bringing the Games back to our city for the first time in a generation and begin a new chapter in Los Angeles' timeless Olympic story," Los Angeles Mayor Eric Garcetti said.
While France's social media lit up with joy, 9,500 km away in Los Angeles, the city was alive with excitement in anticipation of hosting its third Olympic extravaganza, reports Xinhua news agency.
Los Angeles hosted the 1932 and 1984 Games.