After discussing the venture with his neighbors, he put together a football team to play in El Salvador's second division.

Salaverría observed a practice at Llano del Espino, a field on the outskirts of the city where the team was based, but was unimpressed with the quality of the players.

He issued instructions for Once Municipal to be reinforced with second division players such as defender René "Chacuate" Moscoso, a shoemaker.

The team's first season in Primera Division was a success, with Once Municipal finishing first in the national tournament and winning a title.

However, more financial problems led Salaverría to sell Once Municipal's 1959 Primera Division spot to Atlético Constancia (later Alianza F.C.)

They turned to Arturo Simeón Magaña, the landowner of the area around El Zapotón, the field where Once Municipal played.

The Once Lobos were the firm candidate in the league to gain direct promotion and had experienced players such as Memo Rivera and William Renderos, as well as Edwin Portillo as a coach.

However, Once Municipal won 3–2 on the afternoon of 22 May 2004 in an unexpected upset against the Lobos at Estadio Cuscatlán with a hat trick by Colombian Víctor Jaramillo that solidified Once's place at the top of the Segunda Division and its place in the Primera Division the next season, returning to the top tier for the first time in 25 years.

[1] In 2006, the club had its most successful period ever under Nelson Mauricio Ancheta, who filled the roster with players released by more prominent teams.

In 2008, the team was once again relegated to the Second Division due to poor management, coaching errors and the underperformance of high-earning players.

The club was relegated at the end of the next season but were given a reprieve after Atletico Balboa was demoted due to their failure to pay the league.

On 17 January 2018 Once Municipal were stripped of their football license due to unpaid fees to Segunda Division and lack of payments to players and coaches.

Prior to the construction of its stadium, the club trained and played home games at the Llano del Espino in Canchas.