He was born on February 9, 1963, in the city of Bogotá D.C. He entered the Military School of Cadets General José María Córdova on February 6, 1978, graduating as a Second Lieutenant of the Infantry on June 1, 1981.
During his career he has occupied, among others, the following positions: Commander of Special Forces Battalion No. 2, Commander of the Infantry Battalion No. 19 General Joaquin Paris, Commander of the School of Lanceros, Director of the School of Infantry, Commander of the Special Forces Brigade, Commander of the Fourth Brigade, Chief of Planning and Transformation of the Army, Commander of the Air Assault Aviation Division, Commander of the Joint Special Operations Command and Commander of the National Army.
Among other positions, he has served as: Guest Instructor in the US Army Rangers School, Student of the Command and Staff School in Fort Leavenworth United States and Head of the Strategic Review and Innovation Committee “CRE-i “, on two occasions, producing the war plans Sword of Honor (Espáda de Honor) I and II.
General Mejía Ferrero is professional in Military Sciences of the Military School of Cadets and holds a Master’s Degree in International Security of the Naval Postgraduate School (Monterey, California, USA), another in Strategic Studies of the Army College of War in United States (Carlisle, Pennsylvania, USA) and one in National Security, of the School of War of Colombia.
In his combat training he has completed the courses: Lancero (Expert Category) and Paratrooper (Distinguished Category), Jumping Boss, Explorer (US Army), Special Forces and Ranger (US Army).
He has been awarded with several national distinctions, including : Order of Boyacá (Grade Grand Cross), Order of San Carlos (Degree Commander), Order Antonio Nariño (Grade Grand Officer), Order José María Córdoba (Grade Grand Cross) , Cross of the Colombian Air Force (Grand Cross), Order of Democracy (Degree Commander), Distinguished Services in Public Order (for the sixth time), Guardian of the Homeland (two times), Cross to the Police Merit (for the Third Time) , Francisco José de Caldas (Three Occasions), Best Student of the Military School of Cadets (Two Occasions).
Marshal Hermes of the Brazilian Army (Academic Merit), Duke of Caxias of the Brazilian Army (Academic Merit), Minerva of the Chilean Army, (Academic Merit), Medal of Merit of the United States Army, Medal Army Commendation of the United States (Two Occasions), Army Achievement Medal of the United States Army, Medal of Special Operations of the Joint Special Operations Command of the United States.