Greater exposure for the young actor came with the regular role of Alex Whitman on The WB's "Roswell" (1999-2001), a unique hybrid of the teen romantic drama and science fiction genres that earned moderate ratings and spawned a dedicated cult following. As Alex, Hanks played one of three teen humans in on the secret that a trio of their classmates and longtime neighbors are survivors of the famed 1947 UFO crash. Evincing a natural, unforced charm, Hanks was the series' cynic, a relatable, down-to-earth voice of reason and won over sympathetic viewers with his understandable distress at being kept in the dark by his human pals Liz (Shiri Appleby) and Maria (Majandra Delfino) in early episodes, In later episodes when his previously unrequited love for alien Isabel (Katherine Heigl) seemed somewhat reciprocated, audiences cheered for him.
While playing the guy who gets all the girls -- as friends -- didn't mark Hanks as a heartthrob like co-stars Jason Behr and Brendan Fehr, "Roswell" made the actor a familiar face to youth audiences, and he began appearing with supporting roles in teen-aimed features in 2000. He won laughs as the geeky but charming Cosmo in the disappointing "Cyrano de Bergerac" reworking "Whatever It Takes" (2000) and was subsequently featured as Felix, pragmatic friend of the brokenhearted Berke (Ben Foster) in the teen romance "Get Over It" (2001).