Seminario started his career in 1954 playing for Deportivo Municipal where he played until 1959. During this time he made 19 appearances for the Peru national team. On 17 May 1959 he scored a hat-trick against England in a 4–1 win, in Lima.[2]
In 1959 he moved to Europe, joining Sporting CP of Portugal, where he would play 50 matches and score 21 goals, and be nicknamed Expresso de Lima.[3]
In 1961 he moved on to join Real Zaragoza in Spain where he became the top scorer in La Liga (with 25 goals in 30 matches) for the 1961–62 season. Before he was sold to Italy, he would play 8 matches and score 8 goals in the Zaragoza.
^Seminario: "Pichichi Trophy". Archived from the original on 27 October 2009. Retrieved 19 January 2009.{{cite web}}: CS1 maint: bot: original URL status unknown (link)