Álvarez was born in Buenos Aires. His father was a printing worker, and the younger Álvarez's first experience in politics would be in the splinter trade unionCGT de los Argentinos, formed in 1968 by Raimundo Ongaro. He earned his degree in history at the University of Buenos Aires.[1] Álvarez married three times in his youth: Marta Chojo, Gloria López Lecube, and Liliana Chiernajowsky. He had two daughters with his second wife, though his third marriage would be the most enduring.[2] He met Liliana Chiernajowsky, who had spent 7 years as a political prisoner during the Dirty War, shortly after her release in 1981. They had one daughter.[3]
He served as an adviser at the Regional Economies Commission of the Argentine Senate from 1983 to 1989. Álvarez established Unidos in 1985, a periodical in support of the progressive wing of the Justicialist Party that would become influential in Argentine universities through the student organization APU. He was elected National Deputy for the Justicialist Party in 1989, but split from the party shortly afterward over disagreements with President Carlos Menem's turn to the right, creating an independent caucus known as The Group of Eight.[1]
Álvarez joined a group of politicians of different progressive parties, as well as former Justicialists, in 1991 to create the Frente Grande coalition party. He was again elected congressman for the 1993–97 period, as well as a member of the Constitutional Convention that drafted the 1994 amendment of the Argentine Constitution. He took part in the creation of the FrePaSo coalition in 1994.[4] Nominated candidate for vice-president on José Octavio Bordón's ticket, they obtained second place in the 1995 presidential elections.[1]
He retired from public life for five years. His marriage to Liliana Chiernajowsky ended, and his notable later relationships included those with politician Vilma Ibarra and actress Soledad Silveyra.[2] He was appointed as President of Mercosur's permanent representatives committee, CRPM (Comisión de Representantes Permanentes del Mercosur). He took office on 9 December 2005, was reelected in 2007, and served until December 2009.[1] Álvarez underwent vascular bypass surgery in 2009, and recovered.[2] He took office as General Secretary of the Latin American regional trade organization, ALADI (Asociación Latinoamericana de Integración), on 1 September 2011 and served in that capacity for six years.[6]