Discerning a call to the priesthood, Fr. Guerrero attended St. Patrick College Seminary in Los Altos from 1977 to 1981 earning a Bachelor of Arts degree in Psychology. From 1981 to 1984 he attended St. Patrick Seminary in Menlo Park and from 1984 to 1986 he attended the Graduate Theological Dominican School, GTU in Berkeley earning a Masters degree in Divinity in 1986.
Fr. Guerrero was ordained a priest in Honolulu, Hawaii on July 9, 1992 by Most Reverend Joseph Ferrario for the Diocese of Honolulu.
He served as associate pastor in parishes in Hawaii until 1996, when, because of a great desire to minister to the Hispanic community, and a wish to be closer to his family in California, he requested to be admitted to the Diocese of San Bernardino.
Fr. Guerrero was welcomed by the Diocese where he served as parochial vicar at Holy Family in Hesperia and St. Catherine of Siena in Rialto. He was incardinated into the Diocese of San Bernardino in 2001 and was appointed administrator and later pastor of St. Frances of Rome in Wildomar. He has served as Parochial Vicar at St. Theresa Parish in Palm Springs and as Administrator at Our Lady of Guadalupe in Chino where he became pastor in 2010.
Mass of Resurrection was held at Our Lady of Guadalupe Parish in Chino on May 13. He was buried at Our Lady Queen of Peace Cemetery in Colton.