In 2371, Muñiz was part of Miles O'Brien's team aboard the USS Orinoco which assisted Kai Winn Adami and General Lenaris Holem in their search of a blindvault that held the Orb of Contemplation. (DS9 short story: "The Orb of Opportunity")
In 2372, Muñiz was on the Defiant during its mission to resolve problems the Karemma were having by trading with the United Federation of Planets via the Ferengi. After the ship was damaged by entering a planet's atmosphere to rescue the Karemma, Muñiz and Fabian Stevens worked with Worf and O'Brien to repair the ship and destroy the Jem'Hadar fighters. (DS9 episode: "Starship Down")
After O'Brien experienced twenty years of prison left in an Argrathi mental simulation, Muñiz supervised the other crewmen while O'Brien got used to working on the station again. (DS9 episode: "Hard Time")
In early 2373, Muñiz participated in a survey mission to Torga IV to look at the possibility of mining the cormaline that was located there. Muñiz was hit by a Jem'Hadar weapon blast when Kilana and her crew arrived. The anticoagulant in the weapon meant O'Brien was unable to stop Muñiz's bleeding. The crew were also besieged within the crashed Jem'Hadar ship without medical supplies. Muñiz died soon after. On the way back to DS9, O'Brien and Worf kept watch over his body. (DS9 episode: "The Ship")
- DS9 - Prophecy and Change short story: "The Orb of Opportunity"
- DS9 episode: "Starship Down" (First appearance)
- TNG - Slings and Arrows eBook: The Oppressor's Wrong
- DS9 episode: "Hard Time"
- DS9 episode: "The Ship"