Pecson was born in Barrio Libsong in
Lingayen,
Pangasinan as the second child of Victor Tomelden, a census inspector, and Maria Paz Palisoc, a teacher. She gained her elementary and secondary education from Lingayen's public schools and her college education from the
University of the Philippines Manila, where she graduated with degrees in Bachelor of Science and Master of Arts. She began her career as a classroom teacher at the
Manila High School and Ermita Elementary School in 1919. After seven years, she became a teacher and later Principal of the Soler Intermediate School and the Santa Clara Primary School (later known as Gomez Elementary School). In 1934, she began teaching at Far Eastern College (now
Far Eastern University),
Centro Escolar University and the
University of Manila. She eventually joined the faculty of the Zamboanga Normal School (now
Western Mindanao State University) when her husband was assigned to teach there. She married Potenciano Pecson, a teacher and lawyer, who was elected as
representative for the
First District of Pangasinan from 1928 to 1935 and was later appointed an associate justice of the
Court of Appeals in 1953. Pecson also became active in women's groups. She became involved in social work as co-founder, board member, treasurer, and first vice-president of the National Federation of Women's Clubs of the Philippines (NFWCP) and as a
suffragette who advocated for Filipino women's right to vote – which was granted on April 30, 1937, following a
special plebiscite. ==Political career==