Pedro Reyes studied architecture but considers himself a sculptor. His works integrate elements of theater, psychology, and activism and take a variety of forms including penetrable sculptures Cápulas, 2002-08, as well as puppet productions The Permanent Revolution, 2014, and Manufacturing Mischief, 2018.

In 2008, Reyes initiated the ongoing Palas por Pistolas project in which 1,527 guns were collected in Mexico through a voluntary donation campaign to produce the same number of shovels to plant 1,527 trees. This led to Disarm (2012), where 6,700 destroyed guns were transformed into a series of musical instruments.

In 2011, Reyes started Sanatorium, a transient clinic offering brief unexpected treatments mixing art and psychology. Originally commissioned by the Guggenheim Museum, New York, Sanatorium has been in operation at Documenta 13, Kassel (2012), Whitechapel Gallery, London (2013), The Power Plant, Toronto, Canada (2014), and OCA, São Paulo (2015), among 10 other venues.

In 2013, he presented the first edition of pUN: The People’s United Nations at the Queens Museum in New York. pUN is an experimental conference in which ordinary citizens act as delegates from each of the UN countries and try to apply techniques and resources from social psychology, theater, art, and conflict resolution to geopolitics. The second edition of pUN was held at the Hammer Museum in Los Angeles (2015). The third pUN General Assembly took place in December 2015 at the 21st Century Museum in Kanazawa, Japan.

In 2015, he received the U.S. State Department Medal for the Arts and the Ford Foundation Fellowship.

In late 2016, he presented Doomocracy, an immersive theatrical installation commissioned by Creative Time. He held a visiting faculty position at the Massachusetts Institute of Technology during the fall of 2016, and held his residency at MIT CAST as the inaugural Dasha Zhukova Distinguished Visiting Artist. In addition, continuing his work with firearms, Pedro Reyes presented Return to Sender (2020) at the Tinguely Museum in Basel, which consisted of a series of music boxes constructed from gun parts. Each box reproduces a well-known classical piece from the country of origin of the respective manufacturer. For Austria, a music box made from Glock gun parts plays Mozart; for Italy, Beretta guns play Vivaldi, etc., alluding to the fact that the problem of violence begins in the factory where the guns are made.

Recently, Pedro Reyes was commissioned by the Bulletin of the Atomic Scientists together with ICAN, the International Campaign to Abolish Nuclear Weapons, winners of the 2017 Nobel Peace Prize, to raise awareness of the growing risk of nuclear conflict. For this collaboration, he developed Atomic Amnesia, which was presented in Times Square in May 2022. Reyes received the Luxembourg Peace Prize in 2021 for his work on disarmament.