In 1908 he was appointed governor of Iloilo after his predecessor
Benito Lopez was assassinated. Shortly afterwards he was re-elected in his own right and served until 1912. He later served as governor again from 1922 to 1925. In between, he was also active as a lawyer for various sugar plants and banks in the province. Montinola was a member of the
Democrata Party from its founding in 1916. Montinola became one of the leaders of this opposition party until he joined the
Nacionalista Party in the early 1930s. In 1931, Montinola was elected to the
Philippine Senate on behalf of the
7th District. He was a member of the
OsRox Mission to
Washington DC in 1931 that led to the passage of the
Hare–Hawes–Cutting Act, the first law to grant Philippine independence, in the
US Congress. In 1934, he was one of the delegates to the Constitutional Convention where the
1935 Philippine Constitution was drafted. He was also elected vice president of the convention. In 1935, Montinola was elected to the
National Assembly from
Iloilo's
2nd district. In 1938 he was re-elected. ==Death==