After being promoted to National Category, C.D. Lealtad debuts in the Third Division during the 90/91 season with the firm will to perform well. The position achieved, tenth, fulfilled our desires, but even more so because in that season a period of great splendor began, making the decade of the nineties the best in our history up to that moment. The 91/92 campaign was brilliant and in a very close competition where up to six applicants gathered, we managed to sing the alirón beating the second classified by a single point. The league for promotion to second B awaited us and the illusion too, but Real S.D. Alcalá turned out to be too powerful a rival and took away the possibility of promotion even though we surpassed C.D. Carballino and Atlético Astorga F.C. that completed the group. In the 92/93 season we were runners-up just three points behind the Caudal Deportivo de Mieres, repeating the promotion league although with little success as we were bottom-runners with only two points and preceded by Arosa S.C., C.D. Colonia Moscardó and C.D. Ribert, from Salamanca. The 93/94 season was also dominated by Caudal Deportivo with C.D. Lealtad as runner-up, with which we tried again for promotion and with better numbers although Aranjuez C.F. it deprived us of getting it. We were group runners-up with S.D. Fabril and Club Atlético Bembibre in third and fourth position.
In the 94/95 season we were third in the League after Caudal Deportivo and Club Siero, playing a competitive promotion league where equality reigned but on this occasion we were surpassed by C.D. Endesa As Pontes and C.D. Leganés B, while the bottom was U.D. Salamanca B. The 95/96 season was not so favorable and we were eighth, out of the promotion league, to which we would return in the 96/97 campaign again after being fourth. With a single win, we were last behind Burgos C.F., C.D. Ponte Ourense and Real S.D. Alcala. The following year we would experience the best moment in the history of the Club until then and that is that after proclaiming ourselves brilliant League champions with enough solvency, we would finally achieve the dream of reaching the Second Division B with a young Marcelino García Toral on the bench. We had commanded a difficult and even group in the promotion league where S.D. Gimnástica Segoviana was our main adversary and with whom we had to play for promotion on the last day at home, the compromise resolved favorably by winning 1-0 before the immense joy of all the Malian fans who had had to wait more than 80 years to see his team in the bronze category of Spanish football. Betanzos C.F. and Real Madrid C.F. B completed the quartet of teams from that historic league.
We debuted in Second Division B in the 98/99 season with Enrique Mijares as president and Marcelino García Toral on the bench, aware of our limitations, but very excited to play a championship so longed for in a group shared with Asturian, Madrid, and Canary Islands teams. , Galicians and Castilian-La Mancha. Soon it was clear that the challenge was enormously complicated and, despite the great effort of the squad, we were bottom-line players, although we stood up at all times. Back in the Third Division, we were once again proclaimed champions in the 99/00 season, looking out of the corner of our eye at the possibility of being reunited with the bronze category, but a strong A.D. Alcorcón crossed our path in the league and surpassed us. The third was La Bañeza F.C. and the fourth the C.D. Xove Lake.