Pennington was born in Newark, New Jersey, the son of Congressman Alexander Cummings McWhorter Pennington (1810–1867), the second cousin of New Jersey Governor and Speaker of the U.S. House of Representatives William Pennington (1796–1862), and the grandnephew of New Jersey Governor William Sandford Pennington (1757–1826).
William Shakespeare | William Laud | William Blake | William | William III of England | William Morris | William McKinley | William Howard Taft | William Ewart Gladstone | William the Conqueror | William S. Burroughs | William Shatner | William Faulkner | William Randolph Hearst | William Wordsworth | William Tecumseh Sherman | William Hogarth | Prince William, Duke of Cambridge | William Penn | William Jennings Bryan | William Gibson | William Wilberforce | William James | William Makepeace Thackeray | Fort William | William Hanna | William Hague | William III | William Hurt | William Walton |
This family, of Muncaster Castle in Cumberland, descended from William Pennington, who was created a Baronet, of Muncaster in the County of Cumberland, in the Baronetage of England in 1676.