On July 25, 1955, Whittaker became the first full-time employee of Recreational Equipment, Inc. (REI) and was the company's CEO in the 1960s[4] as well as an early board member with American Alpine Club president Nicholas Clinch.

[5] When Whittaker climbed Mount Everest, it provided REI with so much free advertising that the following year, 1964, its gross income topped US$1 million for the first time.

When Kennedy was shot in Los Angeles, Whittaker immediately flew over to comfort RFK's wife when her brother in law had to shut off life-support.

[7] In 1990, he led the Earth Day 20 International Peace Climb that brought together climbers from the United States, USSR, and China to summit Mount Everest.

Whittaker is chairman of the Board of Magellan Navigation, a company that produces handheld Global Positioning System (GPS) units.