John Hancock was president of the Continental Congress when it adopted the Declaration of Independence.
Hancock presided over the Second Continental Congress during the decisive summer of 1776. Congress adopted the Declaration on July 4, after voting for independence through the Lee Resolution on July 2. As president, Hancock signed the official engrossed document, although most delegates added their signatures later, primarily on August 2.
A common mix-up is confusing Hancock's role with that of Thomas Jefferson. Jefferson drafted most of the Declaration, while John Adams, Benjamin Franklin, Roger Sherman, and Robert Livingston helped revise it as the Committee of Five. Hancock was not the document's principal author; he was the presiding officer who authenticated and transmitted it.
Hancock's large, flamboyant signature helped make him one of the Declaration's most recognizable figures. The first printed Dunlap broadsides carried Hancock's name in type as president, alongside secretary Charles Thomson's attestation.