Martinez, who had suffered a heart attack in December, died of a heart attack Sunday while vacationing with his family in Yosemite, said his wife, Faith.
The Pacoima-born Martinez, a former gang member, founded Victory Outreach Church of the San Fernando Valley in 1975, after reaching out to the area's gang members and drug addicts.
The church in Arleta operates a gang intervention program and a rehabilitation center for men in Arleta and one for women in Sunland.
"To me, he was a strong father figure," said Karl Cruz, pastor of the church's Spanish-language congregation. "He had open arms for everybody."
Cruz was one of those whose life was turned around by Martinez's outreach. That was in 1991, when Cruz was a teenage Pacoima gang member spending time in juvenile hall for armed robbery.
"If it wasn't for him having the church here and reaching out and having a prison ministry I wouldn't have had the opportunity to know that my life can really be changed," Cruz said. "They presented Christ to me in a way that related to my lifestyle.
"He was an inspiration to me because of where he came from himself and how he overcame his own struggles."
As Martinez told The Times in 1990: "For 10 years, I roamed the streets of San Fernando. I ended up a drug addict. I know that people in the street can change."
Born in Pacoima on Feb. 20, 1943, Martinez became involved in drugs and gangs at 13. Then, while serving time in Los Angeles County jail in 1965, someone shared the Gospel with him: "He turned his life around because he accepted Jesus Christ as his personal savior," his wife said.
They were married in 1967, a year after Martinez enrolled in the Latin American Bible Institute in La Puente.
Martinez was a pastor at a church in Middlebury, Pa., for two years, then founded the Teen Challenge Center in Ithaca, N.Y. He and his wife later served as missionaries in Durango, Mexico, before returning to the United States in 1973 to begin Martinez's outreach work in the San Fernando Valley.
Church member Steve Martinez is a former gang member whose life changed after the Victory Outreach pastor came to one of the meetings held during the Latino gang truce in the San Fernando Valley in 1993.
"He came in as an elder and mentor, and that's when I started going to his church," said Martinez, who is not related to the pastor. "He always stayed focused on serving the Lord. That was his No. 1 [priority], so anything he could do to help people off the streets, he would do it.
"He didn't know how to sit still, even after his heart attack [in December]. Part of our memory of him will be, even though he was sick, he'd lift his arm and say, 'Go to the streets, go help people.' "
In addition to his wife, Martinez is survived by his daughter, Davina Leyva; his sons, Jonathan and Miguel; his sister, Ramona Galindo; his brothers, Matias, Gregg, Daniel and Jose; and six grandchildren.
Services will be held at 10:30 a.m. Saturday at Shepherd of the Hills Church 19700 Rinaldi St., Porter Ranch.