An all-American leading man with classic good looks, Mark Harmon's easygoing demeanor and graceful maturation eventually led to his settling into an onscreen persona as a world-wise leader of men. A former star quarterback at UCLA, Harmon began acting in the mid-1970s, landing roles on various television series and in the occasional feature film prior to landing the plum role of Dr. Robert Caldwell on the acclaimed medical drama "St. Elsewhere" (NBC, 1982-88). Initially St. Eligius' resident ladies man, Harmon took a tremendous career risk when Caldwell later became the first main character on network television to be diagnosed with AIDS. The actor's calculated risks continued to pay off when he earned kudos for his portrayal of serial killer Ted Bundy in "The Deliberate Stranger" (NBC, 1986), only to be dubbed "The Sexiest Man Alive" by People magazine. Efforts to parlay Harmon's popularity into success on the big screen yielded the moderately popular comedy "Summer School" (1987), although more serious offerings, such as the actioner "The Presidio"(1988) and the little-seen drama "Stealing Home" (1988) failed to lift him to movie star status. Television provided far more fertile ground of Harmon, who, after returning to familiar territory for four seasons on the medical drama "Chicago Hope" (CBS, 1994-2000) landed the biggest hit of his career as the star of the popular crime drama "NCIS" (CBS, 2003- ). An enduring television presence for more than 30 years, Harmon's timeless appeal was undeniable.