Mejía Domínguez was born on 22 February 1941 at the José María Cabral y Báez Hospital in Santiago de los Caballeros, as the first child of Hipólito de Jesús ‘Polín’ Mejía Díaz and María Josefa ‘Marina’ Domínguez Viñals, both native of La Chichigua in Gurabo, place where he was raised. In his hometown he is known as Cabuyita, diminutive for cabuya (Latin American Spanish for “Agave twine”), because of the long blond straight hair that he had during his youth.

Mejía received a high school diploma from the Loyola Polytechnic Institute in San Cristóbal, Dominican Republic, graduating in 1962. Two years later, he attended special programs at North Carolina State University in the United States. On 4 July 1964 he married Rosa Gómez Arias, a third cousin of him. They have four children, among them, Carolina Mejía de Garrigó, a 2016 vice-presidential candidate.

At age twenty-four, he was appointed director and undersecretary of the national Tobacco Institute. In 1978, he was appointed Minister of Agriculture under the government of President Antonio Guzmán Fernández. During this period, agri-business incentive laws were passed and programs to promote rural agriculture development and technification were undertaken.

In 1982, Mejia was defeated in his campaign to become senator from Santiago Province. In 1990, he was named vice-presidential candidate on the ticket of Dominican Revolutionary Party leader José Francisco Peña Gómez.

In 2000, Mejía ran for president as the candidate of the left leaning Dominican Revolutionary Party (PRD) on a program to increase health, education, and social security services through tax hikes. He led the field in the 2000 presidential election, taking 49.87 percent of the vote in the first round. His main opponents, Danilo Medina and former president Joaquín Balaguer, received 24.9% and 24.6% of the vote, respectively.

Mejía’s first presidential campaign in 2000 won him the first Dominican presidency under then new electoral rules that required a “50 más 1” (50 percent plus one of the total votes in order to win in the first voting round.) This was in stark contrast to the late PRD leader, José Francisco Peña Gómez, who unsuccessfully ran for office three times consecutively (1990, 1994 and 1996) and never received the support that Mejia received in his first attempt.

While holding the seat of Head of State, Mejía actively sought to change the then current constitution in order for it to allow consecutive presidential re-elections. This was achieved with the aid of his party’s majority stake at both legislative chambers (Senate and Lower Chamber). The original constitution prevented the previous president from contending against him in 2000.

In March 2004, the Haiti Commission of Inquiry, headed by former US attorney general Ramsey Clark, published its findings : “Noting that 200 US special forces had travelled to the Dominican Republic for “military exercises” in February 2003, the commission accused the US of arming and training Haitian rebels there. With permission from the Dominican president, Hipólito Mejía, US forces trained near the border, in an area used by former soldiers of the disbanded Haitian army to launch attacks on Haitian state property.”