Wellner was born in
Portland, Oregon, and grew up in various cities in the US. His father was United States Forest Service scientist
Charles Wellner. He attended
Ogden High School in Ogden, Utah and graduated in 1963. He went on to attend the
University of Idaho in
Moscow, Idaho, where he earned a Bachelor of Science degree in Mathematics and Physics in 1968. After a brief stint in graduate school at
Yale University in 1969–1970 and serving in the
U.S. Army Signal Corps from 1969 to 1971, he returned to graduate study in statistics at the
University of Washington and received his Ph.D. in 1975 with
Galen Shorack as his advisor. Wellner worked as an assistant professor and associate professor of statistics at the
University of Rochester from 1975 to 1983, after which he moved back to the
University of Washington in
Seattle, Washington and became a professor of statistics. He remained at the University of Washington for the rest of his career, retiring in 2020. == Honors and awards ==