Quinones grew up in Claremont, California. He graduated from Claremont High School in 1977 and then attended the University of California at Berkeley, graduating with B.A. degrees in Economics and American History.
He took his first journalism job in 1987 at the Orange County Register. The next year he moved to Stockton, California, where he spent four years working as a crime reporter for the Stockton Record. In 1992, he moved to Seattle, where he covered county government and politics for the Tacoma News-Tribune.
He left for Mexico in 1994 where he worked as a freelance reporter. Quinones returned to the United States in 2004 and now works for the Los Angeles Times, covering immigration-related stories and gangs.
In 1998, he was selected as a recipient of the Alicia Patterson Fellowship, for a series of stories on impunity in Mexican villages. In 2008, he was awarded a Maria Moors Cabot prize, by Columbia University, for a career of excellence in covering Latin America.
In 2011, he started a storytelling experiment, called "Tell Your True Tale" on his website. The site aims to encourage new Writers to write their own stories. At last count it had more than 50 stories posted.
He has lectured a more than 50 universities across the United States. In 2012, he gave a lecture at the University of Arizona entitled “So Far from Mexico City, So Close to God: Stories of Mexican Immigrants" and of Mexico's Escape from History.”
In 2013, he took a leave of absence from the paper to work on his book Dreamland about the opioid epidemic in America, focusing on abuse of prescription painkillers such as Oxycontin and the spread of Mexican black-tar heroin, primarily by men from the town of Xalisco, Nayarit.
In 2014, Quinones left the Los Angeles Times to "return to freelancing, writing for National Geographic, Pacific Standard Magazine, the New York Times, the Los Angeles Magazine, and several other publications."
Writing for the Los Angeles Times in January 2017, Quinones penned an op-ed piece titled, "The Truth is Immigrants have let us live like Princes." In the article, he writes about the positive economic impact of immigrant workers on the Southern Californian region of the United States.