Alejo was born in Buenos Aires and began his filmmaking career in 2003. At first he started focusing on advertising productions with big format photography, collaborating with photographer Charlie Mainardi on car lighting and at the same time, joining the camera department in film as a video assistant for commercials and feature films. A self-taught cinematographer, Alejo expanded his expertise through experimentation and attended various cinematography courses, complemented by studies in painting and image aesthetics, which have significantly influenced his artistic vision. As the cinematographer and cameraman for Rodrigo Moreno's feature film "The Delinquents", he received the award for Best Cinematography at Premios Sur by Academy of Motion Picture, Arts and Sciences of Argentina 2024. More recently, Alejo filmed the mini-series directed by Mariano Cohn, starring Luis Brandoni and Robert De Niro for Disney+.