He served as both the men's and women's rowing coach at the University of Washington during a 42-year association with the school.

He then transferred to UC Irvine, where he again competed in both swimming and water polo, while adding rowing – becoming captain as a senior.

[2] Ernst began his coaching career in rowing at UC Irvine.

After the retirement of Dick Erickson, he led the Washington men's team from 1987 to 2007, capturing national championships in 1997 and 2007.

[3] The following season, Ernst returned to lead the women's team,[4] a role he held from 2007 to 2015.