He became a Freemason in 1893, being initiated in the Portugal Lodge with the symbolic name of Alaíde, ascending to the 33rd degree, and being part of its Supreme Council since 1934.

With the republican triumph, he was a cabinet chief of Correia Barreto (1910–1911) and then Civil Governor of the Autonomous District of Funchal 1913–1914.

Sá Cardoso was invited again to form government and he was Prime Minister again from 16 to 21 January 1920, accumulating the Interior (same period) and Foreign Affairs (from 29 June to 12 July 1919).

He would participate in another government (of Álvaro de Castro) occupying the post of Minister of Interior between 18 December 1923 and 6 July 1924.

With the 1926 revolution that installed the Ditadura Nacional, a military dictatorial administration that would be followed by António de Oliveira Salazar's authoritarian Estado Novo, Alfredo de Sá Cardoso was again arrested in 1926, and forced to live in a regime of fixed residence, first in Cape Verde and then in the Azores, between 1927 and 1933.