Vicuña was from a powerful family; of his brothers, Francisco Ramón Vicuña was an influential politician, and Manuel Vicuña was Archbishop of Santiago. He is primarily known for his role in the presidential election of 1829. He ran for president, finishing fourth; but rather than appointing the runner-up (or even second runner-up) as vice president, the Congress controlled by his brother's party appointed Joaquín, precipitating a civil war.