Mario Rafael Díaz-Balart y Caballero is an American politician and Republican member of the United States House of Representatives, serving Florida's 26th congressional district since 2003. Born on September 25, 1961, in Fort Lauderdale, Florida, to Cuban exile parents, he hails from a prominent anti-Castro family. His father, Rafael Díaz-Balart, was a Cuban politician and opponent of Fidel Castro, while his brothers include former U.S. Representative Lincoln Díaz-Balart, journalist José Díaz-Balart, and businessman Gustavo Díaz-Balart. As a Cuban-American, Díaz-Balart has been a staunch advocate for policies aimed at isolating the Cuban regime, including support for the Helms-Burton Act and opposition to normalization of relations with Cuba. His family's history of exile from Cuba following the 1959 revolution has deeply influenced his political focus on Latin American affairs, human rights, and immigration reform.

Díaz-Balart began his political career in the Florida House of Representatives, serving from 1987 to 1992, before moving to the Florida Senate from 1992 to 2000. Elected to the U.S. House in 2002 after his brother Lincoln vacated the seat, he initially represented the 25th district and later the 26th following redistricting. His district covers much of northwestern Miami-Dade County, including Hialeah, and portions of the Everglades. Throughout his tenure, he has served on key committees such as Appropriations, Foreign Affairs, and Rules, influencing legislation on foreign aid, disaster relief, and border security. Prior to entering politics full-time, Díaz-Balart worked as a marketing executive in his family's publishing and real estate businesses in Miami.

Known for his conservative ideology and bipartisan approach on certain issues like veterans' affairs and infrastructure, Díaz-Balart has maintained a strong focus on Cuban-American interests. He has been criticized by some for his hardline stance on Cuba but praised for his effectiveness in securing federal funding for Florida. As of his ongoing service, he remains an influential figure in Republican politics, particularly within the Cuban exile community.