Born to a wealthy family from San Borja with political links to the Revolutionary Nationalist Movement, Martínez spent most of his career in local administration, starting as a substitute member of the city's municipal council before being twice elected to a full seat on the body.

Elected in 2011 to lead the fractured opposition caucus, he sought to create a working relationship with the ruling Movement for Socialism but was hampered by internal rebellions within his own bloc, a fact that led to his ouster as leader the following year.

Martínez's parents held longstanding political links to the Revolutionary Nationalist Movement (MNR), his father having been an active participant in the National Revolution of 1952, while his mother—a second-generation Arab immigrant—served as mayor of San Borja.

[4][5] Martínez limited himself to local politics until 2009 when he was invited to seek a seat in the Chamber of Deputies on the slate of candidates presented by National Convergence (CN), a haphazard electoral alliance that incorporated many of the old party structures of ADN and the MNR.

[8] As head of CN, Martínez sought to establish a "proactive opposition" within the legislature, attempting to build bridges and cooperate where he could with the ruling Movement for Socialism (MAS-IPSP), a strategy that was successful inasmuch as it further divided the alliance, accused by dissident factions of being "functional" to the government.

[13][14] Following the end of his term, Martínez retired to his residence in San Borja, where he once again took up ranching and worked to promote rapprochement between the many opposition groups that found themselves at odds following the victory of the MAS in the 2014 elections.