He became a full-time staff writer in 1971 and, as the only Spanish-speaking reporter on the Metro staff for several years, covered topics as varied as the Mexican border, farm labor and the Watergate break-in. He also worked for the foreign desk as a correspondent in Mexico and Central America from 1976 to 1979. Del Olmo became a member of the Times editorial board in 1980, when he also began writing a regular Op-Ed page column on Latino affairs. He was promoted to deputy editorial page editor in 1989, was named assistant to the editor in 1995, and became an associate editor in 1998.

Del Olmo was a member of the team of Times staffers awarded the Pulitzer Prize Gold Medal for Meritorious Public Service in 1984 for a series on Southern California’s Latino Community and won an Emmy Award for writing The Unwanted, a 1975 KNBC documentary on illegal immigration.

Del Olmo was one of the original founders of the California Chicano News Media Association in 1972. He was the chairman of the first national meeting of Latino journalists, in San Diego, 20 years ago. That meeting led to the organization of NAHJ.