He joined All India Mission Seminary, Pilar Goa in 1956.
Aleixo was ordained a priest of Society of the Missionaries of Saint Francis Xavier on 21 December 1969.
He served as the rector of the All India Mission Seminary, Pilar, in Goa.
[6][7] Aleixo was appointed the first bishop of Port Blair on 22 June 1984 by Pope John Paul II and received his episcopal consecration on 20 January 1985 from Pius Kerketta, S.J., Archbishop of Ranchi.
Pope Francis accepted his resignation on 6 January 2019.