Jerusalem has a cast of around 14:
Johnny "Rooster" Byron – opinionated, eccentric, ex-daredevil and teller of fantastically improbable stories, he has a young son whom he rarely sees. He lives in a caravan in the local woods. He holds parties where he gets drunk and supplies drugs, some of them to under-age kids. He has a rare type of blood, and he makes money by selling his blood for transfusion.
Ginger – underdog of the group, older than the others who hang around with Johnny, never having grown out of the lifestyle. He aspires to be a DJ, but is an unemployed plasterer.
The Professor – vague and whimsical yet kind, the elderly professor spouts philosophical nothings and unwittingly takes LSD. He has a good relationship with Johnny.
Davey – young teenage abattoir worker who is best friends with Lee, and visits Rooster regularly for free drugs and alcohol. He can't stand the idea of leaving Wiltshire.
Troy Whitworth – local thug, the same age as Ginger. Troy's stepdaughter goes missing (after it is strongly implied he abuses her); he badly beats Johnny at the end of the play.
Lee – young teenager, enters the play after having been hidden on the sofa asleep. He plans to emigrate to Australia the next day, despite having little money to take with him.
Phaedra – Troy's stepdaughter is seen at the beginning of both Acts One and Two singing the hymn "Jerusalem" and dressed in fairy wings. She is said to have disappeared; at the end of Act Two it is revealed that she is hiding in Johnny's caravan.
Pea and Tanya – two local girls who emerge from underneath Johnny's caravan, having fallen asleep drunk.
Dawn – Johnny's ex-girlfriend and mother to son Marky. Although she disapproves of his life, she kisses him again but there is no reconciliation.
Marky – Johnny's six-year-old son.
Wesley – the local pub landlord, he is involved in the festivities for St George's Day and has been roped into doing Morris Dancing.
Linda Fawcett and Luke Parsons – council officials.
Frank Whitworth – Brother of Troy Whitworth
Danny Whitworth – Younger brother of Troy and Frank Whitworth
