Founding and early years
The team was founded on April 19, 1924 in Monforte de Lemos in a meeting held at the Teatro Principal. It was born out of the merging of Atlétic Club and Monforte FC through mutual agreement. The meeting was chaired by José Ibáñez Fernández, the last president of Atlétic Club, who served as acting president, with Francisco Álvarez González as secretary. The club began life under the name Sociedad Deportiva y de Cultura Física Lemos Club, and took Ramón Taboada Zúñiga as their first president. They also had a new stadium, Stadium Lemos, located on the highway towards Ourense, that replaced the old grounds of As Lamas and A Compañía.
In 1934 the team achieved promotion to Serie A after finishing the season in first place. However, after this the Galician Football Federation sanctioned them for starting a player whose registration wasn't compliant with the rules during a match against Ferrol FC, meaning that in the end it was Ferrol that took the Serie B title. In the 1934-35 season they participated in the Galician Championship for the first time, in which they finished in second place with 13 points and a record of six wins, a draw and three losses, only behind Unión Sporting Club of Lavadores, the team that beat Lemos 2-0 on the final day of the season.
In the following season, however, Lemos claimed the title after overcoming Club Coruña 5-2 in a decisive match. They finished the league in this fashion with 14 points, one more than the Corunnans, and a record of six wins, two draws and two losses. Due to this, Lemos qualified to play in the first round of the Copa de España that year against Deportivo de La Coruña, the aforementioned Unión Sporting Club and Real Stadium Club Avilesino (the latter of which was disqualified), where they finished second in their group and, therefore, didn't manage to qualify for the second round.