He served in numerous positions, most notably as President of the Supreme Council of Military Justice, Chief of Staff of the Army and Director General of the Civil Guard.

Meanwhile, he studied the exact sciences with scarce means and great effort[4] at the University of Córdoba (passing the first year and being the only student at the university to obtain an outstanding grade in mathematical analysis[4]) and prepared for the Military Academy entrance exams, managing to enter the Toledo Infantry Academy on 20 January 1936,[5] forming part of a promotion of officers that would later be known as "the Montaña barracks promotion.

He reported to the 33rd Cádiz Infantry Regiment and fought in that Nationalist unit until the end of April 1937, when he moved to the III Tabor of the 4th Group of the Regulares of Larache.

[10] While in this position, he issued the last General Order of the territory[11] and carried out the last lowering of the Spanish flag in Sidi Ifni, for the retrocession of the colony to Morocco on 30 June 1969.

[14] After the act of lowering and raising the flags, General Vega pronounced the following words:[15]Mr. Minister: It is a great honour for me to represent the Spanish Government before Your Excellency at the ceremony of the handover of Ifni to the Kingdom of Morocco.

My General, we have left here the best of Spain, our desire and our concern has always been to respect the beliefs, customs and habits of the people of Ifni and to contribute to the extent of our ability to the cultural and economic development of its population.

In his teaching role, it is worth highlighting the humanistic side in the training of officers, having studied two years of philosophy and literature at the University of Granada.

When Vega took the floor, he briefly reviewed his military career and assessed the past, present and future of the army, ending with the following reflection:[18] It would be well to remember that ideas must not be confused with ideals.

[20] Even on the side opposite us, there have been people who, perhaps, if they had felt the calling at an early age, would have been magnificent generals and perhaps would not have thought the way they thought, and I am referring to Modesto, Líster, etc., who undoubtedly had some of these military virtues that we are all interested in having, especially in the highest ranks.After having strong disagreements with Manuel Gutiérrez Mellado, at that time first vice president of the government and minister of defence, he resigned his position on 17 May 1978, noting his disagreement with the government policy of military appointments, in effect little respectful of the professional careers of the generals, and also with the reduction of the functions of the JUJEM, pursuant to Royal Decree 836/1978, of 27 March.

[23] On the occasion of the celebration of the golden anniversary of the "Montaña Barracks promotion", on 11 April 1986, he was received in audience by King Juan Carlos I along with the rest of his classmates.