Her assignments there involved overseeing litigation as well as training staff in cases of unfair labor practice. Throughout the 1980s Dudley provided legal counsel on migrant worker issues, senior citizens' rights, and tenants' rights at the Legal Services Corporation, the California Rural Legal Assistance Program, and the National Lawyers Guild Military Law Project. From 1983 to 1987 she was president and executive director of the National Lawyers Guild in New York, overseeing some 8,000 attorneys, law students, and legal workers in the organization's 175 chapters nationwide.

Dudley also taught law and politics courses at the University of California at Berkeley. Prior to joining Greenpeace she was first a program officer and then executive director of the Veatch Program. One of the most progressive grant foundations in the United States, this program distributed some $9 million to organizations around the country to promote such causes as environmental protection and environmental justice issues, community organizing, and rural and urban development.

In September 1992 Dudley, then age of 46, was selected executive director of Greenpeace USA, and officially took up the post on January 1, 1993. At that point Greenpeace had branches in 30 countries, over four million registered supporters and countless enthusiasts worldwide, a staff of 400 full-time members plus part-timers and volunteers in the thousands, and a reported budget of about $150 million. Its funds came exclusively from voluntary contributions, but its finances were said to be in disarray.

Over the years Greenpeace activists served on a number of fronts, often mobilizing spontaneously, indiscriminately, and without much planning in order to stop whaling, prevent dumping of toxic and nuclear wastes, or campaign against nuclear development and weapons. In the course of doing so Greenpeace militants acquired—indeed, often-times consciously encouraged and sought—a confrontational image. Dudley's successful nomination as executive director of one of the main branches, Greenpeace USA, ushered in a more media-savvy approach, though she conceded in one speech before the Stanford Graduate School of Business that "we supply the media with the sound bites they need. That's what brings us the support of the public." By the late 1990s, Greenpeace press releases offered a contact person "on site"—that is, at the demonstration— who could be reached via a cellular phone number.

Dudley's priorities involved first coordinating the efforts of nearly two million supporters across the United States; integrating activities and consulting with Stephen Sawyer, her predecessor and beginning in 1992 executive director of Greenpeace International, headquartered in Amsterdam; and finally, redefining the group's principal objectives. Accordingly, under Dudley's influence Greenpeace outlined for itself four major campaign areas: atmosphere and energy, ocean ecology and forests, toxins, and disarmament. It also recognized a need to broaden its support base, attempting to connect with minorities and the disadvantaged, while also pointing up the greater impact of environmental degradation upon the world's poor.

Equally significant, Greenpeace appeared to be shifting away from attention-grabbing stunts. Instead of being daredevils for the environment—scrambling up smokestacks in Michigan to protest sulfur dioxide emissions and acid rain, or putting themselves in inflatable boats between whales and Russian whaling vessels—Greenpeace lobbyists worked harder at strengthening legislation that protects the atmosphere, conserves dwindling natural resources, and encourages alternative energy sources. As mirrored in Dudley's own career, Greenpeace was in the process of giving up its flair for the outrageous; becoming savvy in the use of computers, the media, and a global communications network; and stimulating the world community to see "mutual security" in the larger, environmental sense by practicing the arts of lobbying and compromise. Her tenure at Greenpeace USA ended in the summer of 1997, when she resigned to pursue other interests.

There is little published material on Barbara Dudley. Some of her writings, speeches, and activities can be accessed on the Internet by doing a search for "Barbara Dudley" of "Greenpeace" on the World Wide Web (August 5, 1997).