[2] Altamirano would establish himself as a starter for Huachipato during 2018, and scored his first professional goal on October 20, 2018, in a 2–0 home win against Unión La Calera.
[3] In a match against Deportes Antofagasta on August 12, 2019, Altamirano scored his first career hattrick during a 4–3 home win at Estadio CAP.
[4] He'd make his international club competition debut for Huachipato on February 12, 2020, starting in a 1–0 home win against Deportivo Pasto for the 2020 Copa Sudamericana first stage, in an eventual second round exit.
[5] Altamirano was a starter during Huachipato's 2021 Copa Sudamericana campaign, scoring his first club international goal in a 1–1 home draw against Rosario Central in an eventual group stage exit.
[9] After taking part in training microcycles of Chile's squad at under-23 level,[10] Altamirano made his international debut in a friendly match against Cuba on 11 June 2023 as a starter.