William Daniels had already played two presidents of the United States: John Adams in the Broadway and film productions of 1776, and again in the TV miniseries The Rebels, and John Quincy Adams on the TV miniseries The Adams Chronicles, but in 1999, he decided to try for the real-life presidency of the Screen Actors Guild. He ran against incumbent Guild, two-term president Richard Masur, and won, becoming only the fourth challenger in Guild history to do so. By then, Daniels had been a performer for over 65 years, on stage, radio, television, feature films, and had won two Emmy awards for his portrayal of Dr Mark Craig on St. Elsewhere. In 1986, Daniels and his wife, Bonnie Bartlett, who played his wife Ellen Craig on St. Elsewhere, both won Emmys for their work on the show -- becoming the first real-life married couple to win a major acting award on the same night.
At age 4 1/2, he made his performing debut tap-dancing. Three years later, he and his five year-old sister Jacqueline, became a song-and-dance team on radio programs, children's show, clubs and benefits. They often appeared on the Nick Kenny Radio Hour and, after early TV performances on The Horn and Hardart Children's Hour, hosted by Ralph Edwards (of This is Your Life fame), Daniels, Jacqueline and younger sister Carol formed their own radio show The Daniels Family. At age 15, Daniels understudied the roles of sons John and Clarence Jr., in a road company of the hit play Life With Father. Hired as a cast replacement for the play's Broadway production, he performed the role of John and, later, Clarence Jr. for 2 1/2 years. He later served in the military as a staff sergeant with Armed Forces Radio, then enrolled in Northwestern University where he met and married fellow drama major, Bonnie Bartlett. The first important break of his adult career came when the legendary playwright Tennessee Williams chose him for the major role of "Brick" in the national company tour of Cat on a Hot Tin Roof, which he played for 33 weeks.
Daniels' presidency saw the beginning of high-profile members' return to the Board room: at the December 1999 plenary meetings, the National Board voted to amend the Guild's "conflict of interest" rule, which had so long prevented members with production interests from holding office. During Daniels' tenure, the Guild conducted the longest strike in entertainment union history, over radio and television commercials, lasting from May through October 2000; released two major studies, The African-American Television Report and Still Missing; Latinos in and Out of Hollywood; debuted CastSag on the website; participated (along with the Directors Guild of America and the Writers Guild of America) in an entertainment labor issues roundtable discussion with Secretary of Labor Alexis Herman; conceived the Global Rule One campaign; hired a new National Executive Director/CEO, A Robert “Bob” Pisano, from outside the Guild (for the first time in our 68-year history); and commenced a major Guild reorganization. Daniels decided not to seek the presidency a second time when his two-year term ended in 2001, but served as a temporary board replacement. On September 23, 2004 Bonnie Bartlett and he both won 3-year seats on the Board of Directors