Penny Clark was born to Fred R. and Marjoire Anemone Orton Clark in Kansas. She received a bachelor's degree in Education and a master's degree in U.S. History from Emporia State University in 1982 and 1985, respectively. In 1992, Clark received another master's degree in Historical Administration and Museum Studies from the University of Kansas, with a focus in archives.

While pursuing her second master's degree, Clark worked as an archivist at the American Academy of Family Physicians Foundation in Kansas City, Missouri from 1991 to 1992. Upon graduating, Clark worked as an archivist and museum curator for the Sam Houston Regional Library and Research Center in Liberty, Texas.

In 1999, Clark began working as an archivist at the Tyrrell Historical Library in Beaumont, Texas until 2008. In 2009, Clark became the University Archivist for Lamar University in Beamount, Texas. With her work as University Archivist, Clark served on a variety of university committees focused on her areas of expertise in history and records management, as well as in other administrative areas. Clark also received a fellowship from the Center for History and Culture of Southeast Texas and the Upper Gulf Coast at the University to research Novaline Baldwin, a Beaumont, TX resident of the 19th and early 20th centuries.

With her work as an archivist, Clark has written several historical articles for publications through organizations including the Texas State Historical Association, Texas Gulf Historical and Biographical Record, and the Heritage of the Great Plains. Clark has also written articles and presented at conferences for the Society of Southwest Archivists and the Texas Oral History Association, in addition to serving on the board of directors for both organizations. Much of Clark's historical work has focused on local history and women’s history in the southeast Texas area, particularly during the Civil War and World War II eras.

Clark has also written or co-edited the following books: Farm Work and Friendship: The German Prisoner of War Camp at Lake Wabaunsee (1988), a publication of her master's thesis; On Our Way to “The Big Day” (and Beyond): The Hundredth Anniversary of the Lucas Gusher at Spindletop (2002); and Beaumont's Civil Air Patrol in World War II (2021).

Outside of her professional responsibilities, Clark has served on a number of community committees, including the Beaumont Music Commission (2002-2004), the Golden Triangle Sierra Club Board of Directors (2016), and the Big Thicket Association Board of Directors (2017). Clark has also served in leadership positions at the Beaumont Heritage Society, Southeast Texas Genealogical and Historical Society, and the Texas Gulf Historical Society.