Born in Pontevedra in Galicia, Pazos managed several small clubs in his native region before moving to S.C. Braga of the Portuguese Primeira Liga as an assistant to compatriot Fernando Castro Santos.
He succeeded the latter for the second half of the 1997–98 season, losing the Taça de Portugal final 3–1 to FC Porto.
On 6 November, his team defeated La Liga title holders Valencia CF – managed by his friend Rafael Benítez – on penalties in the Copa del Rey.
In June 2015 his company was interested in buying Real Avilés Industrial CF, until the club was unexpectedly relegated to the Tercera División.
[9] In the 2019 Spanish local elections, Argibay joined En Marea as a consultant on sporting issues.