Guillermo Alfonso Maripán Loayza made his Chilean first league debut in 2012 with Universidad Católica, his training club. He emerged as a strong defender in the 2015/2016 season, in which he plays 37 matches and wins the 2015 and 2016 Primera Division, as well as the 2016 Chile Supercup.
After a full season in 2016/2017 (38 matches), he joined Deportivo Alavés.
In the last two seasons, the athletic central defender (1.93m) has played 47 matches with the Spanish club, showing solid and unyielding determination.
A Chilean international selection 21 times, the central defender contributed to the run of Chile during the 2019 Copa America, reaching the semi-final of the tournament.