Poe was found on September 3, 1968, in Iloilo City by a woman, in the holy water font of Jaro Metropolitan Cathedral, the main church of the city.

In 1975, Poe attended elementary school at Saint Paul College of Pasig and Saint Paul College of Makati. In 1982, Poe transferred to Assumption College San Lorenzo for high school. Following high school, Poe entered the University of the Philippines Manila (UP), where she majored in development studies. She transferred to Boston College, where she graduated with a degree in political science in 1991. She interned for William Weld’s campaign while in college.

Poe married Teodoro Misael Daniel “Neil” Vera Llamanzares on July 27, 1991. Llamanzares is a natural-born Filipino who held American citizenship since birth until April 2016. He is a veteran of the United States Air Force who served from 1988 to 1991 and later worked for Science Applications International Corporation. He worked for San Miguel Corporation after the return of his wife to the Philippines.

On April 16, 1992, Poe gave birth to her son, Brian, a journalist who worked as a reporter for CNN Philippines. She later gave birth to two daughters: Hanna in 1998, and Nika in 2004. Her family lived in Fairfax, Virginia, for 12 years.

Poe worked as a preschool teacher at a local Montessori education-style school in 1995. In 1998, she left her job as a teacher to work as a procurement liaison officer at the United States Geological Survey. In 2005, she was made Vice President and Treasurer of her father’s film production company, FPJ Productions, and was put in charge of maintaining the company’s archive of over 200 films.

Poe is a natural-born Filipino. On October 18, 2001, Poe acquired U.S. citizenship by naturalization. She reacquired her Philippine citizenship and in October 2010, she renounced her American citizenship, as per the RA 9225 law.

In 2003, Poe’s father, Fernando Poe, Jr., announced that he was entering politics, running for President of the Philippines in the upcoming election under the Koalisyon ng Nagkakaisang Pilipino (KNP) against then-President Gloria Macapagal-Arroyo. Poe returned to the Philippines to help him campaign, but returned to the United States afterward.

Fernando Poe, Jr. was rushed to the hospital after a stroke later that year. Grace immediately returned to the Philippines, only to arrive shortly after her father had died on December 14, 2004. Following her father’s death, Poe and her family decided to return permanently to the Philippines on April 8, 2005, in order to be with her widowed mother.

While Poe herself admitted that her biggest strength in the campaign was her surname, she also conceded that it would be insufficient for her to be elected simply on that alone, emphasizing that her platform is just as important as her name in getting her elected to the Senate. She also dismissed claims that her candidacy was her family’s revenge against her father’s loss in 2004, saying that all she wants to do is serve should she be elected to the Senate. A day after the election, Poe was announced as among the winners with her having the highest number of votes. She was officially proclaimed a senator by the COMELEC board in May 2013, along with fellow Team PNoy candidates Chiz Escudero, Sonny Angara, Alan Peter Cayetano, and Loren Legarda, as well United Nationalist Alliance candidate Nancy Binay (who did not attend, opting instead to send her lawyer to represent her).

In the 2010 general election, Poe served as a convenor of Kontra Daya. She also became honorary chairperson of the FPJ for President Movement (FPJPM), the group which was organized to pressure her father to run in 2004, continuing the movement’s social relief programs for the less fortunate. On October 10, 2010, President Benigno Aquino III appointed Poe to serve as chairwoman of the Movie and Television Review and Classification Board (MTRCB). She was sworn in on October 21, 2010, at the Malacañang Palace and was later reappointed by President Aquino for another term on October 23, 2011.

Although Poe was rumored to be running for senator as early as 2010, it was not confirmed that she would stand for election until October 1, 2012, when President Aquino announced that she was selected by the administration Team PNoy coalition as a member of their senatorial slate. Poe filed her certificate of candidacy the next day on October 2, 2012. Although running under the banner of the Team PNoy coalition, Poe officially ran as an independent. Poe was also a guest candidate of the left-leaning Makabayang Koalisyon ng Mamamayan. Until February 21, 2013, Poe was, along with Senators Loren Legarda and Francis Escudero, one of three common guest candidates of the opposition United Nationalist Alliance (UNA) of Vice-President Jejomar Binay.

Analysts noted the rapid rise of Poe in national election surveys, which community organizer Harvey Keh attributed to popular sympathy for her father, fueled in part by high public trust in the Poe name. Prior to the start of the election season, Poe was ranked twenty-eighth in a preliminary survey conducted by the Social Weather Stations (SWS) in mid-2012, before the start of the filing period. Immediately after filing her candidacy, Poe initially ranked fifteenth in the first survey of the election, published by StratPOLLS. While she ranked as low as twentieth in a survey published by SWS later in the year, she entered the top 12 in January 2013, where she stayed. In the last survey issued by Pulse Asia in April 2013, she was ranked third.

In the 2013 elections, Poe ran on an eleven-point platform promising to continue the legacy of her father. Her labor legislative agenda also includes more opportunities, skill development and growth for Filipino workers, employment security for the disabled and handicapped, and protection of workers in the informal sector. Specific policies she advocated in the course of her campaign include reviving the national elementary school lunch program first introduced during Marcos Era, the installation of closed-circuit television cameras in government offices, and stricter penalties against child pornography, continuing her earlier advocacy during her time at the MTRCB. In addition, she has also advocated against Internet censorship.

In 2015, Poe led the legislature’s investigations into the Mamasapano clash, which left 44 Special Action Force members dead.

On September 16, 2015, Poe, together with Francis Escudero, declared her presidential bid, in front of hundreds of supporters, family and friends at the Bahay ng Alumni, University of the Philippines, Diliman, Quezon City under the newly coalition of Partido Galing at Puso, composed of Bagong Alyansang Makabayan and is led by the Nationalist People’s Coalition. Former Philippine President and Mayor of Manila Joseph Estrada has given his support to her. On her speech announcing her presidential bid, Grace Poe laid down a 20-point program of government if she would be elected.

In June 2015, United Nationalist Alliance (UNA) interim president and Navotas City Representative Toby Tiangco claimed that Poe lacked the 10-year residency requirement for a presidential candidate. There was an issue about Poe’s certificate of candidacy (COC) for senator in 2012 for the 2013 Philippine Senate Elections, in which she had stated that she had been a resident of the Philippines for six years and six months. Tiangco stated that even during the time of the 2016 Presidential Elections, Poe would still be six months short of the residency requirement.

On November 17, 2015, the Senate Electoral Tribunal opted to drop the cases against her. The decision was affirmed on December 3, 2015. In their judgment on the case, the SET declared that Grace Poe, a foundling, is a “natural-born Filipino”, which allowed her to retain her seat in the Philippine Senate. David filed a motion for reconsideration to reverse the ruling by SET, which was rejected on December 3, 2015, after which he filed an appeal with the Supreme Court. On December 1, 2015, the COMELEC’s second division disqualified her as presidential candidate due to failing to meet the “10-year requirement” for residency. Under COMELEC rules, the party or coalition supporting her may file a substitute before December 10, 2015. On December 11, the commission’s first division also disqualified Poe. The first division, voted 2–1 in favor of the petitions to disqualify and cancel her certificate of candidacy. These decisions were appealed to the COMELEC en banc, which on December 23, 2015, formally disqualified Poe from running as president in the 2016 elections for failing to meet the 10-year residency requirement. Poe said she would appeal the disqualification to the Supreme Court. On December 28, 2015, the Supreme Court issued two temporary restraining orders against the decision of the COMELEC en banc.

Poe was widely speculated to be a potential presidential or vice presidential candidate in the 2016 general elections, with possible running mates such as Rep. Leni Robredo and Senator Miriam Defensor-Santiago. Poe placed first on a presidential preference poll issued by Pulse Asia In June 2015 with a rating of 30%, outranking previous front runner Vice President Jejomar Binay, who had a 22% rating. She also placed first in the vice-presidential poll, with a 41% preference nationwide. In an opinion survey issued by Social Weather Stations (SWS) in June 2015, Poe also placed first, with a 42% preference. She also placed first in SWS’ vice-presidential poll, with a 41% rating.

On March 8, 2016, voting 9–6, the Supreme Court voted to affirm Poe’ natural-born status and 10-year residency. On April 9, 2016, the Supreme Court declared their ruling as final and executory.

In November 2016, Poe voted in favor of a resolution, filed by senator Risa Hontiveros, which sought to reject the burial of the late dictator Ferdinand Marcos in the Libingan ng mga Bayani.

Poe is in favor of the passage of the Anti-Discrimination Bill (now SOGIE Equality Bill). The LGBT sector was one of the sectors she prioritized and thanked during her 2016 presidential bid. She was not in favor of same-sex marriage during a 2013 interview and instead was in favor of domestic partnership, however, she changed her mind and announced her all-out support for same-sex marriage in 2016, the first and only presidential candidate in Philippine history to do so.

During her presidential campaign in 2016, Poe was in favor of the death penalty, but only in cases that involves heinous crimes. However, in 2017, she had a change of heart and began to speak out against the reintroduction of the death penalty law after seeing the justice system and law enforcement in the country.

In February 2017, she voted in favor of the Tax Reform for Acceleration and Inclusion Act or TRAIN Law. After the inflation rate increased due to the law, Poe said that she voted in favor because President Duterte ‘needed funds’. On the same month, Poe did not support the resolution declaring that the Senate has a say in the termination of any treaty or international agreement. On December 13, 2017, she voted in favor of the extension of martial law in Mindanao.

On May 17, 2018, Poe was among the senators who voted in favor of a resolution calling on the Supreme Court to review its decision granting the quo warranto petition and ousting Chief Justice Maria Lourdes Sereno. In June 2018, she voted in favor of a national ID system. In September 2018, Poe announced her bid for re-election in the Senate. On October 15, she filed her certificate of candidacy for senator.

In 2019, after the 2018 Philippine third telecommunications provider bidding, Poe chaired the committee which allowed the telecommunication franchise of Mislatel, composed of China Telecom and businessman Dennis Uy’s Udenna Corp and Chelsea Logistics. The approval was controversial because of the company’s connection to China, Chinese security threats, and its violations to Philippine franchise laws. Despite this, on February 6, Poe gave the green light for the company’s endorsement to the plenary.

On May 13, 2019, Poe was reelected to the Senate with over 22 million votes, coming in second, only behind fellow Senator Cynthia Villar.