Welch's father was a journalist and eventually became editor of the News Tribune in Tacoma. Welch graduated from the University of Washington and worked for the Cleveland Plain Dealer and the Seattle Times before joining the P-I in 1935. Welch published stories and articles in national magazines including the Saturday Evening Post. One Post story, "Miss Union Station," was made into the first original television show.
It was Welch who persuaded band leader Victor A. “Vic” Meyers (1898-1991) to run for mayor of Seattle in 1932. Welch had intended the campaign as a gag, to enliven the mayor's race. Meyers lost, but the stunt launched Meyers on a political career that took him to the office of lieutenant governor for 20 years. Welch also founded the Olympic Grill Roundtable, which gathered influential people together to discuss and act upon serious issues.
On May 26, 1968, Douglass Welch died at age 61. He succumbed to a heart attack at his typewriter at home.