Diosdado Pangan Macapagal (September 28, 1910 – April 21, 1997) was a Filipino statesman who served as the 9th President of the Philippines. He was elected in 1961, defeating the re-election bid of Carlos P. Garcia. He did not win in his own re-election bid in 1965, losing to Ferdinand Marcos. He was also known by his nickname "The Incorruptible".
His daughter, Gloria Macapagal-Arroyo, is the current president of the Philippines.
He finished his law degree in 1936 and was the bar topnotcher when he took the bar examination in the same year with a rating of 89.95%. He worked as a lawyer for an American employer in Manila, and was assigned as a legal assistant to President Manuel L. Quezon.
During the Japanese occupation of World War II, Macapagal served as support to the anti-Japanese task force and as an intelligence liaison to the US guerillas. It was during this period that his first wife, Purita Dela Rosa died. He had two children with Purita Dela Rosa, Cielo and Arturo. Cielo later on became vice-governor of Pampanga. He later married Evangelina Macaraeg, the mother of current Philippine President Gloria Macapagal Arroyo.
In 1948 he served as second secretary to the Philippine Embassy in Washington, DC. At the urging of then-Pampanga governor Joe Lingad, Macapagal ran in the 1949 general elections for a seat in the House of Representatives, representing the 1st District of Pampanga. He won the election and was re-elected in the 1953 general elections, serving in the 2nd and 3rd Congress. While serving in Congress, Macapagal was named as a Philippine representative to the United Nations General Assembly three times.
In the 1957 general elections, he ran for Vice President of the Philippines under the Liberal Party banner as the running-mate of Jose Yulo. While Yulo was defeated by Carlos P. Garcia of the Nacionalista Party, Macapagal was elected Vice-President, defeating the Nacionalista candidate, Jose Laurel, Jr. by over 8 percentage points. Macapagal served out his 4-year term as Vice-President as the de facto leader of the opposition, and benefited from the increasing unpopularity of the Garcia administration. In the 1961 presidential election, Macapagal ran against Garcia and defeated the incumbent president by a 55% to 45% margin.
In 1971, Macapagal was elected president of the constitutional convention that drafted what became the 1973 constitution.