Nicknamed El Chunche (The Thing),a Montero is widely known for his humble origins, which molded his behavior and charisma.

[2] His colloquial lexicon includes phrases such as chollarse las nalgas ("bust your buttocks"), which he uses as his motto to denote effort.

Montero, however, did not exclusively use #20 during his Alajuelense tenure as he used #12 on occasion between 1990 and 1991, and #3 (belonging to fellow defender Hernán Fernando Sossa) at least once during the 1990–91 season—Montero himself mentioned that he did this out of need due to the actual #20 shirts not being readily available.

A few years after his retirement, Montero became assistant to manager Oscar Ramírez at Belén,[11] then coach with Municipal Grecia in the second division.

[12][13] After two seasons there, he became assistant head coach in his beloved team, Alajuelense and gained the CONCACAF Champions' Cup in 2004 and the national tournament in 2005.

[17] In August 2017, Montero was promoted back to the first team as assistant coach to newly hired manager Wílmer López.