William Whipper was born in Lancaster, Pennsylvania, on February 22, 1804. Little has been recorded about Whipper's childhood. His mother Nancy was an African-American servant for his father, a European-American lumber merchant who lived in Little Britain Township in Pennsylvania. In 1836, Whipper married Harriet L. Smith.

William Whipper's father requested his son have a good education from his very early days as a child. His father saw to it that the same tutor who educated Whipper's half-siblings taught William reading and writing. His education helped Whipper become a well-known member of literary societies by the time he reached his twenties. He became a lecturer on moral reform. In the 1820s, Whipper relocated to Philadelphia, and he took a job as a steam scourer. Whipper delivered his addresses at various locations, such as conventions or small meetings. At the age of 24, Whipper published his famous speech "Address on Non-Resistance to Offensive Aggression." This address has been highly praised for its early allusions to what became some of the same nonviolent strategies utilized during the civil rights movements of the 1960s. The piece suggests implementing a nonviolent means of moral righteousness in order to encourage a peaceful political movement towards change. In 1834, Whipper opened a free labor and temperance grocery store in Philadelphia, Pennsylvania, next to the Bethel Church. In 1835, he returned to rural Pennsylvania, moving to Columbia. Upon moving, Whipper married Harriet L. Smith and formed an exciting business partnership with Stephen Smith, an African-American entrepreneur. Their organization accumulated a great wealth, and the two men were considered to be two of the wealthiest African-Americans in antebellum America. Whipper used his newfound wealth to further his causes and his fight for moral reform and abolition.

Whipper wrote and produced many essays dealing with abolition of slavery. He contributed numerous articles and letters to various abolitionist papers like the Liberator, the North Star, and the National Antislavery Standard. In 1835, he attended the annual convention of the Improvement of Free People of Color. He urged delegates to adopt a resolution, which ended the usage of the word "colored." Because of his persistence, the delegates decided to organize a society that would have no racial boundaries. The convention later formed the American Moral Reform Society and gave Whipper credit as a founding father. He served as editor of the National Reformer, the journal of the AMRS. While living in Columbia, Whipper offered his home as a safe place for those traveling the Underground Railroad. He spent almost $1,000 annually to assist those trying to escape from slavery.

Whipper never received any formal awards for his writings, but he is considered to be the forerunner of a civil rights movement who preceded the works of Martin Luther King Jr. and Gandhi. In his "Address on Non-Resistance to Offensive Aggression," Whipper equated non-violence with a sense of reason.

William Whipper died on March 9, 1876, in Philadelphia, Pennsylvania.