Monterrosa distinguished himself preceding his 1963 graduation from the Escuela Militar Capitán General Gerardo Barrios military academy. Monterrosa went on to take military classes at the School of the Americas (SOA) in Panama, and later went on to Taiwan to study anti-communist insurgency tactics. Soon after his return to El Salvador, Monterrosa was assigned to become the leader of the elite and controversial Atlacatl Battalion. The Atlacatl Battalion was held responsible for the El Mozote Massacre. Monterrosa was allegedly seen arriving by helicopter by a local guide prior to the start of the massacre, as told by reporter Mark Danner; however, Danner also reported that Monterrosa had been contacted by a U.S. military advisor to share the outcome of the battle that had taken place in El Mozote. At that point, Monterrosa was in the Atlacatl's headquarters. According to Danner's story, after the conversation with the U.S. advisor, Monterrosa boarded a helicopter and headed to Morazan. The Washington Post reported in 2007 that Monterrosa had ordered the massacre. El Mozote was a tiny village located North of Morazan.
Monterrosa was known to be obsessed with destroying the pro-rebel Radio Venceremos, which "specialized in ideological propaganda, acerbic commentary, and pointed ridicule of the government". Monterrosa was a supporter of President José Napoleón Duarte's efforts to hold peace talks in 1984, and his death seriously weakened them.
There are several versions of how Monterrosa was killed. One is that a malfunctioning helicopter crashed and killed its occupants including Col. Monterrosa. Another version states that an FMLN booby trap was set under a fake rebel radio transmitter that Monterrosa took with him as a victory trophy, in 1984. The bomb went off while he was in flight. Remnants of his helicopter can be found in the Museum of the Revolution in Perquin, Morazan department.
The museum of El Salvador's Armed Forces has designated a special section for Monterrosa. After his death in October 1984, the Salvadoran congress honored Monterrosa with the title of "Heroe de Joateca" and declared him a national hero for his service to the country.
In 2019, the new Salvadoran President Nayib Bukele ordered the removal of Monterrosa's name from one of the main military units of the Salvadoran Army. Years earlier, another Salvadoran president, Mauricio Funes, asked for forgiveness from the state and the people of El Salvador for the crimes committed by state actors during the civil war, and directed the Army to review their behavior in those years. 
- Mark Danner. 1993. The Massacre at El Mozote. New York: Vintage.
- Manuel Roig-Franzia (January 29, 2007). "Former Salvadoran Foes Share Doubts on War". The Washington Post. Archived from the original on November 4, 2012. Retrieved May 1, 2010. Cite uses deprecated parameter
- Mark Danner (December 6, 1993). "The Truth of El Mozote". The New Yorker. Archived from the original on 4 November 2012. Retrieved 4 November 2012. Cite uses deprecated parameter
- William M. LeoGrande (1998). Our Own Backyard: The United States In Central America, 1977–1992. University of North Carolina Press. p. 263. Retrieved 4 November 2012.
- José Angel Moroni Bracamonte and David E. Spencer (1995). Strategy and Tactics of the Salvadoran Fmln Guerrillas: Last Battle of the Cold War, Blueprint for Future Conflicts. Greenwood Publishing Group. p. 140. ISBN 9780275950187. Retrieved 4 November 2012.
- "A killer, reviled: El Salvador stops honouring the leader of the El Mozote massacre". economist.com (registration or subscription). The Economist. 8 June 2019. p. 33-34 (2 columns). Retrieved 29 July 2019.
- BBC Mundo (June 3, 2019). "Nayib Bukele asume en El Salvador: quién era Domingo Monterrosa, el militar vinculado a la masacre de El Mozote y protagonista de la primera orden del presidente salvadoreño". The New Yorker. Archived from the original on 6 June 2019. Retrieved 5 June 2019. Cite uses deprecated parameter