Ernest "Ernie" Prang was the driver of the Knight Bus .
Harry Potter first encountered Prang in 1993 , when he was picked up by the Knight Bus after leaving his aunt and uncle's home. Stanley Shunpike , the driver of the night bus, sometimes calls Ernie by his nickname: Ern. When Harry was taken to the Leaky Cauldron Ernie followed him and was forced to leave the place by the Minister . Ernie was also present at Albus Dumbledore funeral in 1997 . Besides little is known about Ernie, they are known to have an owl look, due to their hair and many wrinkles on their head.
Prang is described as an elderly wizard with very thick glasses giving him an "owl appearance". Ernie doesn't talk much (letting Stan Shunpike do it, preferring to concentrate on driving). His driving skills leave a lot to be desired as he frequently drives at high speed, getting off the road and objects jumping out of his way (mailboxes, lampposts, trees, etc.), moreover, he normally turns corners in a way violent and every time the bus stops, it does so abruptly.
The name Ernie also belonged to one of JK Rowling's grandparents, the other is called Stanley, which was the name given to Ernie's assistant: Stanley Shunpike. His last name is a play on words, like "prang" which is slang for "destroy a car".
Behind the scenes
In the film adaptation of "Harry Potter and the Prisoner of Azkaban ", Ernie is portrayed by the late actor Jimmy Gardner.