"For the first time in 200 years of the Republic, there will be a woman president and she will be transformative," the candidate said in a statement in Spanish on social media. "Thanks to each and every Mexican. Today we demonstrate with our vote that we are a democratic people."
Sheinbaum was expected to receive at least 58% of the vote, according to a sample vote count, the Instituto Nacional Electoral said on social media.
Who is Claudia Sheinbaum?
Claudia Sheinbaum, the former head of the government of Mexico City and candidate for the ruling Morena party, is projected to be the country's first female president, marking a historic achievement in a country known for its deeply patriarchal culture.
The 61-year-old rode the wave of popularity of her longtime political ally, the outgoing leftist Mexican President Andrés Manuel López Obrador, and their Morena party.
The Electoral Court must still validate the presidential election, and if confirmed, she will start her presidency on October 1.
Sheinbaum, a former climate scientist, entered the campaign as the favorite, according to February and March polls by Mitofsky, Parametría, and De las Heras Demotecnia, which placed her support between 49% and 67% compared to her political rivals.
Sheinbaum holds a degree in physics and a master's and doctorate in energy engineering. She has received several accolades for her academic career.
Born in Mexico City in 1962, she has two children and one grandchild. Her partner, Jesús María Tarriba, whom she met at university while both were studying physics, is currently a financial risk specialist at the Bank of Mexico.
In 2018, she became the head of government of Mexico City, the first woman elected to this position. Her desire to be part of Mexican politics began in 2000 when she was appointed Secretary of the Environment for the Federal District under Andrés López Obrador's administration until 2006.
Three year before she became the first woman elected as the head of the Tlalpan borough, serving until 2017. In early 2018, she joined the government of Mexico City as head until June 2023, when she stepped down to run for the presidency with the Morena party, of which she is a founder, aiming to succeed her party colleague, López Obrador.
As part of her campaign within Morena, Sheinbaum is designated the coordinator for the Defense of the Transformation, whose mission, as stated on her LinkedIn profile, is to defend and promote the values of the Fourth Transformation of Public Life in Mexico, the central axis of López Obrador's policy.
Much of her life has been dedicated to university teaching, focusing on renewable energy and climate change. In 2007, the Intergovernmental Panel on Climate Change (IPCC), to which Sheinbaum contributed, received the Nobel Peace Prize.
Sheinbaum is not only the first female president in Mexico, but the first president with Jewish heritage, although she rarely speaks publicly about her personal background and has governed as a secular leftist.
What challenges lie ahead?
Violence has loomed large in this election, the bloodiest in Mexico's history. Dozens of political candidates and applicants have been killed by criminal organizations trying to influence those coming into power.
The poll is seen by some as a referendum on the policies of outgoing President Andrés Manuel López Obrador who is Sheinbaum's mentor.
López Obrador's popular social welfare has helped poorer Mexicans but his "hugs, not bullets" policy of not confronting cartels has not stopped criminal violence.
Mexico's homicide rate is among the highest in the world, and more than 100,000 people remain missing in the country. It also remains a dangerous place to be a woman, with sky-high femicide rates for the region - with figures showing around 10 women are murdered every day.
Sheinbaum will have to act quickly on Mexico's organized crime and security issues, said Will Freeman, a fellow for Latin America studies at the Council on Foreign Relations.
"It's stunning that the governing party could win re-election by a landslide as it seems... given the sweeping violence, the thing is the opposition didn't seem to put together a much more credible set of proposals about what they would do," Freeman said.
Sheinbaum comes with a team from her time as Mexico City mayor that has a proven record on improving security but it remains to be seen if she can replicate that on a national scale, Freeman said.
US-Mexico relations
Both Mexico and the US are holding elections in 2024, something that happens only once every 12 years - and comes at a time of transition in the relationship between the two countries.
Sheinbaum will assume office just a month before Americans head to the polls in November, where immigration is a top issue on the ballot for Joe Biden and Donald Trump.
Mexico is a key US ally on a range of issues, from trade to cracking down on drug trafficking to managing migration. Current and former US officials have frequently described the relationship between President Joe Biden and Mexico's President Andrés Manuel López Obrador as friendly and professional - and anticipate a productive relationship with Mexico's next president.
But Mexico's election also comes at a critical time for the Biden administration.
In recent months, the US has relied heavily on Mexico to step up immigration enforcement and help stem the flow of migration to the US southern border. The election in Mexico has raised uncertainty in the minds of some Biden officials about what, if anything, will change with a key partner when it comes to border cooperation.
One of the considerations in rolling out a new border executive action was doing so after Mexico's election. The administration will likely need buy-in and assistance from Mexico to execute the order.
Officials expect that a new administration in Mexico would likely continue cooperating with the US on migration given years of partnership, but it's unclear how migrants - and especially, smugglers - might plot their next moves in a moment of government transition.
ABC News and CNN contributed to this post.