Senator Nicolas Buendia was born in Malolos, Bulacan on March 12, 1879 to Saturnino Buendia and Petrona Buidon. He learned his first letter under General Teodoro Sandiko in Malolos. He Studied at Colegio de San Juan de Letran and obtained a degree of Bachelor of Arts in Liceo de Manila. He was admitted to the Philippine Bar in 1910.
During the insurrection against Spain, he was a first lieutenant of the Infantry of the Philippine Revolutionary Army, and during the American regime he was Municipal Secretary, Municipal Councilor and Municipal president of Malolos. For a term he served as provincial governor of Bulacan. He was one of the founders of the Philippine Independent Church. In 1934 he was elected delegate to the Constitutional Convention from the first district of Bulacan.
A Nationalist-Democratic by political party affiliation and Aglipayano by religion, he served as senator from 1941-1945.