- Lillian Gish
- The Girl - Marie Stephenson
- Robert Harron
- The Boy - Douglas Gordon Hamilton
- Dorothy Gish
- The Little Disturber
- Adolph Lestina
- The Grandfather
- Josephine Crowell
- The Mother
- Jack Cosgrave
- The Father of the Boy
- Kate Bruce
- The Mother of the Boy
- Ben Alexander
- The Boy's Littlest Brother
- Marion Emmons
- The Boy's Other Brother
- Francis Marion
- The Boy's Other Brother
- Robert Anderson
- Monsieur Cuckoo
- George Fawcett
- The Village Carpenter
- George Siegmann
- Von Strohm
- Fay Holderness
- The Innkeeper
- L. Lowry
- A Deaf and Blind Musician
- Eugene Pouyet
- A Poilu
- Anna Mae Walthall
- A French Peasant Girl
- Yvette Duvoisin
- A Refugee
- Herbert Sutch
- A French Major
- George Nichols
- A German Sergeant
- Mary Gish
- A Refugee Mother
- Mary Hay
- A Dancer
- Erich von Stroheim
- A German Officer
- Noël Coward
- The Man with the Wheelbarrow / A Villager in the Streets (as Noel Coward)
- Bettie Mae Clarke
- Nursing Infant
- Mae Clarke
- Nursing Mother
- Elizabeth Asquith
- Nurse
- Walter Bytell
- Von Tirpiz
- Alphonse Dufort
- A Poilu
- Jean Dumercier
- A Poilu
- Louise Emmons
- (uncredited)
- Valerie Germonprez
- Red Cross nurse
- Edward Grey
- Self - British Secretary of State for Foreign Affairs Addressing House of Commons
- D.W. Griffith
- Self (in prologue for British release)
- John Harron
- A Boy with a Barrel
- Mary Harron
- A Wounded Girl
- Mrs. Harron
- A Woman with Daughter
- Tessie Harron
- A Refugee
- Lady Lavery
- Nurse
- Jules Lemontier
- A Stretcher Bearer
- David Lloyd George
- Self - the British Prime Minister (in prologue for British release)
- Georges Loyer
- A Poilu
- Diana Manners
- Nurse
- Gaston Riviere
- A Stretcher Bearer
- Bettine Stuart-Wortley
- Nurse
- René Viviani
- Self - the French Premier Addressing French Chamber of Deputies
