Alphonse Gallegos was born in Albuquerque on 20 February 1931, nearly blind; two operations gave him some sight, but it worsened through his life until it was almost gone. He joined the Augustinian Recollect friars and was ordained a priest.
From 1972 he was pastor of San Miguel Church in Watts, Los Angeles, where he became known as the 'chaplain of the low riders', the street gangs of Latino youth. On 4 November 1981 he was consecrated auxiliary bishop of Sacramento, and was remembered there as the 'Bishop of the Barrios'.
On the night of 6 October 1991, as his car was being pushed to the side of the road, he was struck and killed instantly by another car; the accounts differ on whether his own car had broken down or he had stopped to help a stranded motorist. He was buried at St. Mary Cemetery, and in 2010 his remains were brought to the National Shrine of Our Lady of Guadalupe in Sacramento. Pope Francis recognised his heroic virtue in 2016.