Luís Hemir Silva Semedo entered Benfica's academy in 2016 at under-15 level, signed a training contract in December 2018 and turned professional in August 2020.

A tall centre-forward who held the ball up and attacked crosses, he was a prolific scorer in the youth ranks and featured in the UEFA Youth League, scoring the winning goal for Benfica in the 2022 Under-20 Intercontinental Cup. He was integrated into Benfica B from January 2022 and played in the Liga Portugal 2 across two seasons, making 21 appearances and scoring twice while also captaining the under-19 side.

He did not appear for the first team in a competitive fixture. With his contract due to expire and no agreement reached on new terms, he left as a free agent in June 2023, joining Sunderland on a five-year deal.

Loans to Juventus Next Gen in 2024-25 and to Moreirense in 2025-26 followed, the latter bringing him back to the Primeira Liga, before he returned to Sunderland. He has represented Portugal at under-20 level.