Founded in 1916 by a group of young people at the Worker's Athenaeum, Lealtad played in regional leagues until 1990, when it was promoted for the first time to
Tercera División. In 1998, with
Marcelino García as coach, the club achieved its first promotion ever to
Segunda División B after defeating
Real Madrid "C",
Betanzos CF and
Gimnástica Segoviana in the promotion playoffs. It only remained in the third tier one season and spent fifteen more seasons in Tercera before being promoted again in 2014, after overcoming a critical economic situation in 2012, by beating
CD Puertollano in the shootout of the
group champions' play-off. This time, Lealtad avoided relegation after beating
Racing Ferrol in the last match of the
2014–15 season by 1–0. In the
2015–16 season, Lealtad achieved a great year with a 10th position, the best ever in the club's history. After four seasons in the third tier, Lealtad would be relegated to Tercera División in April 2018, after receiving an 8–0 defeat from
Bilbao Athletic. On 24 October 2018, Lealtad achieved their first
Asturian Copa Federación by defeating
Sporting de Gijón B after a
penalty shootout. The team finished the
2018–19 league season without losses in the Group 2, but failed to promote to Segunda División B after failing to beat firstly
Getafe B and later
Villarrobledo. ==Stadium==