Born in the hippie hamlet of Woodstock, NY, Martini has Italian roots on his father's side and was partially raised abroad, spending time in both Italy and Canada. Showing promise as a football player, Martini gave that pursuit up after an injury, and dabbled in acting while still in his youth. With his slightly scruffy good looks, he began winning small TV parts during the mid-'90s, and soon scored supporting roles in two major films, "Contact," the alien-encounter movie starring Jodie Foster, and Steven Spielberg's sweeping World War II saga "Saving Private Ryan," featuring Tom Hanks and an expansive cast of both screen veterans and newcomers like Martini. Although the streak of big feature productions didn't continue for him, he signed on as a regular to the hyped-up sci-fi series "Harsh Realm," created by "X-Files" mastermind Chris Carter. Despite its potential, the show didn't survive long. In 2000, Martini joined the cast of another tech-oriented series, "Level 9" (UPN, 2000-01; Syfy, 2008), but it too met a quick demise. Relegated primarily to TV-movie spots and recurring roles, Martini started to rebound slightly with his runs on the high-profile shows "24" and "CSI: Miami." These gigs undoubtedly helped him win the regular part of short-fused Army sergeant Mack Gerhardt on "The Unit," playwright and filmmaker David Mamet's first significant foray into series television. Martini portrayed the fierce military man throughout the show's entire four-season tenure, along with Dennis Haysbert, Robert Patrick and Scott Foley. Mamet also provided Martini with a bit part in his martial-arts film "Redbelt" (2008), which featured a bravura performance by Chiwetel Ejiofor. After "The Unit" disbanded, Martini went back to guest stints on major shows, appearing briefly on the crime comedy "Castle" (ABC, 2009-16) and in numerous episodes of the scheme-centric series "Revenge," where he pined for Madeleine Stowe's affluent lead character. Martini finally returned to features prominently in 2013, when he portrayed Herc Hansen, half of a father/son robot-operating team in Guillermo del Toro's monster-battling movie "Pacific Rim." Sharing many scenes with co-stars Charlie Hunnam and Idris Elba, Martini played a key figure in the super-sized production, leading to greater visibility. That fall he followed up with another notable project, playing a SEAL soldier in the tense sea-set drama "Captain Phillips," starring Tom Hanks and based on a real-life hostage situation.