 Mariano Moreno had several contacts with groups seeking the removal of Cisneros, but was not strongly involved with the May Revolution, which considered the fall of the Junta of Seville a reason to depose the viceroy and create a local junta. At the time, Moreno was still loyal to Álzaga. He attended the May 22 open Cabildo, but according to the father of Vicente Fidel López and the father-in-law of Bartolomé Mitre (both direct witness) he stayed silent at one side and did not join the debate. He voted for Saavedra's proposal: to remove viceroy Cisneros and replace him with a Junta. Manuel Hermenegildo Aguirre, captain of hussars, proposed that the Cabildo take the reins of government, with five men appointed as counselors, Moreno among them. However, nobody else voted for that proposal, and it was the only one that included him. Moreno felt betrayed when the Cabildo twisted the results of the open Cabildo and created a Junta that would be headed by Cisneros. He refused any further contacts with the revolutionaries and stayed home during the remaining events. The definitive members of the Junta came from a popular petition signed on May 25, which was given to the Cabildo. The reasons of Moreno's inclusion in the list are unclear, as with all other members of the Junta. A commonly accepted theory considers it to be a balance between Carlotists and Alzaguists.
