Currently gearing up for his second term in office as President Josiah Bartlett on television's critically acclaimed "The West Wing," Martin Sheen's convincing portrayal of the fictional US President is just the latest in a long line of believable characterizations that began back in the late 1950s.

Ramon Estevez was the seventh of ten children born to a Spanish immigrant father and Irish mother in Dayton, Ohio in 1940. He adopted his stage name after intentionally flunking his college entrance exam so he could move to New York and study acting. He took "Martin" from a friend and "Sheen" from popular Bishop Fulton J. Sheen. By 1964 the young actor had made it to Broadway in "The Subject Was Roses," (which he would recreate on film in 1968) and later headed to Hollywood where he found regular work on television.

It wasn't until the early 1970s, however, through a combination of film and television work that Sheen's talents became universally recognized. In 1973 he garnered enormous attention playing a Charles Starkweather-inspired killer on a spree in Badlands opposite fellow up-and-comer Sissy Spacek. The following year he appeared in two of the most lauded television productions of the era, as the convicted deserter in "The Execution of Private Slovik," and as Robert Kennedy in "The Missiles of October."

Prolific in his appearances on both the large and small screens, Sheen's film career has been largely overlooked with one rather extreme exception; he starred in Francis Ford Coppola's Apocalypse Now (1979), a film that became famous for its excesses and Sheen's near-fatal heart attack during the grueling shoot, an experience he later recalled in the Emmy-winning documentary "Hearts of Darkness: A Filmmaker's Apocalypse." Among his many other films appearances are The Cassandra Crossing, The Little Girl Who Lives Down the Lane, The Final Countdown, Gandhi, That Championship Season, The Dead Zone, The Believers, Wall Street, Da, Cadence, The American President, Monument Avenue, and O.

Credit: amctv.com