Penniman was named Executive Director in 2014 when Fund For The Republic and Americans for Campaign Reform merged to form Issue One.
Penniman was executive director of the Huffington Post Investigative Fund, which he founded with Arianna Huffington in 2009. Supported by large foundations and The Huffington Post, the operation established a nonprofit newsroom of journalists who reported on a variety of topics, most notably the financial crisis of 2007-2008 and its aftermath. The fund was profiled in media publications like the American Journalism Review and the Columbia Journalism Review. In 2011, it merged with the Center for Public Integrity.
Penniman founded the American News Project and served as the Washington director of the Schumann Center for Media and Democracy, where he worked closely with broadcaster Bill Moyers. Moyers and Penniman first met in 1999, when Penniman was running a national grassroots organization called the Alliance for Democracy, which focused primarily on campaign finance reform.
From 2005-2006, Penniman was the publisher of The Washington Monthly magazine. Before that he was the executive editor of a progressive news and opinion website called TomPaine.com perhaps best known for the "op ads" it regularly ran on the opinion page of the New York Times.
He has served on multiple nonprofit boards and advisory boards, including the Homeless Empowerment Project, which publishes Spare Change News, the Center for Responsive Politics and the Roosevelt Institution.
He graduated from St. Lawrence University in 1992 with a degree in philosophy. While there, he started a number of student groups, was a member of the executive committee of the Thelomathesian Society (the student senate), an adviser to the board of trustees and the recipient of the top prize for poetry writing.
In 2016, Penniman and co-author Wendell Potter published Nation on the Take: How Big Money Corrupts Our Democracy And What We Can Do About It. Nation On The Take details the history of money in politics and exposes legalized corruption and the effects it has on everyday Americans. The New York Journal of Books stated, "Nation on the Take is breathtaking in the level of detail for Washington K Street transgressions and the national landscape of politics and money. If you are still on the sidelines for your personal campaign to restore our democracy, this book will incite a riot in your conscience and illustrate some things we as a people can do to take back our country. This book is no less than a clarion call to the American people to rise up and release these ties that bind."
Penniman grew up in St. Louis, Missouri, where he attended the St. Louis Country Day School. His father, Nicholas G. Penniman IV, was publisher of the St. Louis Post-Dispatch and a senior executive with Pulitzer, Inc.
- Joseph, Andrew (2012-01-03). "New Group Formed To Limit Political Money - Influence Alley". Influencealley.nationaljournal.com. Retrieved 2012-01-13.
- "Nation On The Take". Nation On The Take. Retrieved 2016-03-23.
- "a book review by Roberta E. Winter: Nation on the Take: How Big Money Corrupts Our Democracy and What We Can Do About It". www.nyjournalofbooks.com. Retrieved 2016-04-11.
- Board of Directors, Everglades Foundation
- Pulitzer Report Contains Lots of Clues, St Louis Journalism Review, May 1999, by Charles L Klotzer