Stiers was born in Peoria, Illinois, the son of Margaret Elizabeth (née Ogden) and Kenneth Truman Stiers. He attended Urbana High School as a freshman; one of his classmates was Roger Ebert. Stiers moved to Eugene, Oregon, where he graduated from North Eugene High School and briefly attended the University of Oregon. He later moved to San Francisco, where he performed with the California Shakespeare Theater, San Francisco Actors Workshop, and the improv group The Committee, whose members included Rob Reiner, Howard Hesseman and Peter Bonerz. Stiers studied at the Juilliard School (Drama Division Group 1: 1968–1972). During his studies, Stiers was mentored by actor John Houseman and would later join his City Center Acting Company.
Stiers first appeared in the Broadway production The Magic Show in 1974 in the minor role of Feldman. Subsequent early credits include The Mary Tyler Moore Show, Kojak, and Rhoda. Stiers also appeared in the pilot of Charlie's Angels as the team's chief back-up.
In 1977, Stiers joined the cast of the CBS-TV sitcom M*A*S*H. As Major Charles Emerson Winchester III, Stiers filled the void created by the departure of actor Larry Linville's Frank Burns character. In contrast to the buffoonish Burns, Winchester was a well-spoken and talented surgeon who presented a different type of foil to Alan Alda's Hawkeye Pierce and Mike Farrell's B.J. Hunnicutt. Burns usually served as the butt of practical jokes instigated by Pierce or Hunnicutt, and his surgical skills were often harshly criticized. Winchester, however, presented a challenge to his colleagues' displays of irreverence because his surgical skills could match or even outshine their own; his aristocratic manner and aversion to puerile behavior served as the target for his fellow surgeons' barbs and jokes. At times, however, Winchester could align himself with Pierce and Hunnicutt and, a few tantrums aside, he held considerable admiration for his commanding officer, Harry Morgan's Col. Sherman T. Potter. For his portrayal of the pompous but nonetheless multifaceted Boston aristocrat, Stiers received two Emmy Award nominations.
After M*A*S*H completed its run in 1983, Stiers expanded his work on television with regular guest appearances on North and South; Star Trek: The Next Generation; Murder, She Wrote; Matlock; Touched by an Angel; Wings; and Frasier, along with a recurring role in Season 1 of Two Guys and a Girl as Mr. Bauer. In 1984, he portrayed United States Olympic Committee founder William Milligan Sloane in the NBC miniseries, The First Olympics: Athens 1896. Beginning in 1985, Stiers made his first of eight appearances in Perry Mason made-for-TV movies as District Attorney Michael Reston. He had guest appearances on ALF and Matlock. He appeared in two unsuccessful television projects, Love & Money and Justice League of America (as the Martian Manhunter). In 2002, Stiers started a recurring role as the Reverend Purdy on the successful USA Network series The Dead Zone with Anthony Michael Hall. In 2006, he was cast as the recurring character Oberoth in Stargate Atlantis.
Stiers has provided voice work for dozens of film and television projects. His first work was on one of George Lucas' earliest films, the critically acclaimed THX 1138, in which he was incorrectly billed as "David Ogden Steers". Stiers has voiced PBS documentary films such as Ric Burns' project New York: A Documentary Film, 2010 Peabody Award winner The Lord is Not on Trial Here Today and several episodes of the documentary television series The American Experience, including Ansel Adams (2002), also directed by Ric Burns. In 1992, he voiced Mr. Piccolo in the animated English-dubbed version of Porco Rosso. He collaborated with Disney on eight animated features, including 1991's Beauty and the Beast (as Cogsworth, also providing the opening narration), 1995's Pocahontas (as Governor Ratcliffe and Wiggins), 1996's The Hunchback of Notre Dame (as the Archdeacon), 2001's Atlantis: The Lost Empire (as Mr. Harcourt), and 2002's Lilo & Stitch (as Jumba Jookiba). He lent his voice to the direct-to-video Batman: Mystery of the Batwoman (2003) as the Penguin. Stiers did voice work for Solovar in a two-part episode "The Brave and The Bold" of Justice League and voiced Solovar again in a Justice League Unlimited episode "Dead Reckoning". He voiced characters in two of Disney's animated TV series: Gryzlikoff from Darkwing Duck, and Mr. Jolly from Teacher's Pet. He voiced the king and prime minister in the 2004 short film The Cat That Looked at a King. In Hoodwinked (2005), the animated movie partly based on Little Red Riding Hood, Stiers voiced the role of Nicky Flippers, the frog detective who is dispatched to Granny's house. He voiced Pop's father, Mr. Maellard, in the animated TV series Regular Show, which debuted in 2010. Stiers had voices in several video games, including Icewind Dale, Kingdom Hearts II, Kingdom Hearts: Birth by Sleep, as Jeff Zandi in Uru: Ages Beyond Myst, and as Esher in Myst V: End of Ages.
Stiers is the associate conductor for the Newport (Oregon) Symphony Orchestra and the Ernest Bloch Music Festival. He has guest-conducted over 70 orchestras around the world, including the Oregon Mozart Players, the Vancouver Symphony, the Oregon Chamber Players, the Yaquina (Oregon) Chamber Orchestra, as well as orchestras in San Francisco, San Diego, Los Angeles, Chicago and Toronto.