Joselu was Real Madrid Castilla's top scorer in the 2010–11 season, alongside Álvaro Morata, but the team failed to win promotion in the playoffs. On 21 May 2011, he made his first-team – and La Liga – debut, coming on as a substitute for Karim Benzema for the last ten minutes of a home fixture against Almería: he scored almost immediately from a Cristiano Ronaldo cross, making it 8–1 to the hosts.
On 20 December 2011, in his second official appearance for the main squad, Joselu replaced Benzema in the 77th minute of the home match against Ponferradina, for the season's Copa del Rey. He scored the goal to make the match 4–1 two minutes later, in an eventual 5–1 win.