Born to a first-generation Cuban immigrant couple and raised in the Washington, D.C., area, Laz Alonso gravitated to acting interests at an early age, but temporarily forsook the arts in favor of a more practical and well-grounded education, studying business at nearby Howard University's marketing program. After graduation, Alonso left the District of Columbia and took off for the Big Apple, where he worked as an investment banker, but footlights and soundstages beckoned, and with the encouragement of friends, Alonso began auditioning for acting assignments and soon landed appearances in a string of commercials, then guest roles on series programs including CSI, The Practice, and Navy: NCIS, before gracing the casts of theatrically released features. Meanwhile, the young performer -- who had studied classical piano formally for nearly a decade -- parlayed his melodic interests into reggaeton performances and also involved himself in a big way with altruism, launching a nonprofit group for children of single-parent households.
Alonso's big-screen projects included the 2003 urban horror comedy Leprechaun: Back 2 tha Hood; the 2005 Constantine (with a role as a security guard in a morgue), and the 2005 Jarhead (as a soldier stationed in the Gulf War). He worked for Roland Joffé (The Killing Fields) as a detective hot on the trail of a serial killer, in that filmmaker's critically despised torture porn outing Captivity (2007), then essayed a small supporting turn in the same year's Dirty Sexy Money on ABC. Also in 2007, Alonso played a frat boy at an African American college in Atlanta in director Sylvain White's teen comedy-cum-dance film Stomp the Yard. At about the same time, the young actor worked under the aegis of Spike Lee in that helmer's World War II-era period drama Miracle at St. Anna (2008), and signed to act in director James Cameron's hotly anticipated, mega-budgeted science fiction epic Avatar (2009).