Mascarene was born in 6 June 1902 in Trivandrum into a Latin Catholic family. Her father, Gabriel Mascarene, was a government official of the Travancore State. She attended the Maharaja’s College Travancore earning double MA in history and economics in 1925. She went on to earn a degree in law at the Maharaja’s Colleges for Arts and Law, Trivandrum, following her return from a teaching stint in Ceylon.
Along with Akkamma Cherian and Pattom Thanu Pillai, Mascarene was one of the leaders of the movements for independence and integration of the Princely States within the Indian nation.
In February 1938, when the political party Travancore State Congress was formed, she became one of the first women to join. The party goal was to establish a responsible government for Travancore and it was led by Pattom Thanu Pillai as president under whom served K. T. Thomas and P. S. Nataraja Pillai, secretaries, and M. R. Madhava Warrier, treasurer. Macsarene was appointed to the working committee and also served on the party’s publicity committee.
In 1938 and 1939, Mascarene served on the Economic Development Board of the Travancore government. During her time in the state legislature, she became a powerful speaker and enjoyed policymaking In 1942, Mascarene joined the Quit India Movement and two years later was elected as secretary of the Travancore State Congress.
In 1946, Mascarene became one of the 15 women who were elected to the 299-member Constituent Assembly of India, tasked with drafting the Constitution of India. She served on the Assembly’s select committee that looked into the Hindu Code Bill.
Mascarene was elected to the First Lok Sabha as an independent candidate from the Thiruvananthapuram Lok Sabha constituency in the 1951 Indian general election. She was the first woman MP from Kerala and one of only 10 elected to Parliament in those elections. In the second General Elections of 1957, she was defeated in Thiruvananthapuram by S Easwaran, coming fourth in a contest that also featured her erstwhile colleague in the Travancore Congress, Pattom Thanu Pillai.
Annie Mascarene died in 1963 and her grave lies at the Pattoor cemetery in Thiruvananthapuram. A bronze statue of Annie Mascarene was built at the Annie Mascarene Square at Vazhuthacaud in Thiruvananthapuram and it was unveiled by Vice President Hamid Ansari in September 2013.