Drew Douglas Pettus was born in Long Beach, California, in 1946. When he was twelve years old, his parents separated and he came with his mother to Bellingham, Washington. He attended Western Washington University in Bellingham for one year, then left school to work on a project for U.S. Representative Lloyd Meeds. He completed his undergraduate degree at the University of California, Berkeley, in 1971. In 1970, he and Mary Catherine May were married. In 1974, he earned a degree from the Northwestern School of Law, then entered into private law practice in Bellingham until 1976, when he joined Meeds' staff as assistant counsel for the House Rules Committee. He then served as chief of staff for Meeds’ successor, U.S. Representative Al Swift. Pettus worked primarily on immigration and trade legislation, and helped to author the 1980 Northwest Power Act. In 1989, he returned to private law practice in Washington, D.C., and focused on immigration and environmental law. In 1994, he returned to Bellingham and began his own law firm, which focused on immigration law.

The Northwest Power Planning Council is a four-state regional planning body formed by Congress through the Northwest Power Act of 1980 to develop and maintain regional conservation and electric power plans and a fish and wildlife program. The council is composed of two representatives from each member state: Oregon, Washington, Idaho, and Montana. The mission of the council is "to preserve the benefits of the Columbia River for future generations." The body was originally known as the Pacific Northwest Electric Power and Conservation Planning Council; the name was shortened to Northwest Power Planning Council in October 1981, and in 2003, the name was changed to the Northwest Power and Conservation Council.