Boag was born to Wallace B. and Evelyn G. Boag. He joined a professional dance team at age nine, later established his own dance school, and by the age of 19 had turned to comedy. He toured the world's stages in hotels, theaters and nightclubs. While appearing at the London Hippodrome in Starlight Roof, he brought a young 12-year-old girl on stage to help with his balloon act. The girl, a young Julie Andrews, astonished the audience with her voice and was kept in the show. In 1945, Boag signed a contract with Metro-Goldwyn-Mayer and appeared in films such as Without Love and The Thrill of a Romance, albeit uncredited.
In the early 1950s, while appearing in revues in Australia, he met tenor Donald Novis. It was Novis who got Walt Disney to audition Wally for the Golden Horseshoe Revue, a 45-minute stage show which was written by its first pianist Charles LaVere and lyricist Tom Adair. Novis was the show's first tenor and was replaced by Fulton Burley when he retired in 1962. Both Wally and The Golden Horseshoe Revue were cited in The Guinness Book of World Records for being the longest running revue in the history of show business. The 10,000th performance of the Golden Horseshoe Revue was featured on NBC's The Wonderful World of Disney.
Boag's Pecos Bill/Traveling Salesman character was a fast-paced comedy routine featuring slapstick humor, squirt guns, a seemingly endless supply of broken teeth which he would spit out throughout the routine, and his signature balloon animals (Boagaloons).
In 1963, Julie Andrews once again performed with Boag on the Golden Horseshoe stage along with the Dapper Dans, at a special press-only event to promote the following year's release of Mary Poppins. Together, Andrews and Boag recreated their act of long ago and sang "By the Light of the Silvery Moon."
While Walt Disney was alive, he did everything he could to further Wally's career. Boag voiced Jose in "Walt Disney's Enchanted Tiki Room" and also wrote much of the script for the attraction, participating also in the development of "Haunted Mansion" in Disneyland.
Disney had small roles written for Wally in The Absent-Minded Professor and Son of Flubber. It was Disney's intention to use Wally as the voice of Tigger in Winnie the Pooh, but Disney died in 1966 and the role ultimately went to Paul Winchell.
In 1971, Wally took his Pecos Bill character to the newly-opened Walt Disney World and re-crafted the saloon show into a faster, funnier Diamond Horseshoe Revue. Three years later he returned to Disneyland and finished his career there, entertaining adoring crowds at the Golden Horseshoe, retiring in 1982. The Golden Horseshoe Revue closed in 1986. In 1995, Wally was inducted into the ranks of the Disney Legends and has his own window on Main Street in Disneyland above the Carnation Company. The inscription reads "Golden Vaudeville Routines - Wally Boag - Prop."
Wally's performances have influenced many later performers and comedians, most notable of whom is Steve Martin, who studied Boag's humor and timing while working at Disneyland as a teenager. Boag's performance appears on Week One of the Mickey Mouse Club DVD collection, and the soundtrack of the Golden Horseshoe Revue has been released on CD.
Wally is currently working on his autobiography, entitled "The Clown Prince of Disneyland", which is to be published in 2008. He lives in California with his wife, Ellen Morgan Boag.