This came out of a never ending source if improvement on Widipedia but it is the latest information I could find.
Jean Clemens 1880–1909 The youngest daughter of Mark Twain. She had epilepsy from age fifteen, which her father attributed to a childhood head injury. Her epilepsy was not successfully controlled and at one point she was sent to an epilepsy colony in Katonah, New York. She was found dead on Christmas Eve in her bath aged 29. The cause of death was reported as drowning due to epilepsy. 
Derek Bentley 1933–1953 Hanged, aged 19, for a crime his partner committed, Bentley had epilepsy and a mental age of 11. He was pardoned after a 45 year campaign, which included the film Let Him Have It, starring Christopher Eccleston. 
Emilie Dionne 1934–1954 The third of the Dionne quintuplets. Emilie's epilepsy was only made public after her death at a convent in Sainte Agathe, Quebec. She died from the complications of a series of epileptic seizures. These were recorded at noon the previous day, 11pm, 3am, and 5am, but no doctor was called until after her death. Her death from epilepsy caused alarm, leading H. Houston Merritt to inform the public that "the mortality rate among epileptics is no greater than among non-sufferers". 
Virginia Ridley 1948–1997 A woman who had agoraphobia, hypergraphia and epilepsy. Her eccentric husband Alvin was charged with her murder but cleared after the jury accepted that she may have suffocated during a seizure. She had not been seen outside her home for 25 years. 
Don Craig Wiley 1944–2001 A protein-structure biochemist. He kept his epilepsy secret, did not treat it, and died under mysterious circumstances, possibly owing to a seizure. 
Barry George born 1960 Initially convicted but later acquitted of murdering the kins born 1975 English reality television contestant (The Apprentice, I'm a Celebrity, Get Me Out of Here!) and businesswoman, who developed epilepsy as a teenager 
Daniel Tammet born 1979 An autistic savant who is gifted with a facility for mathematics problems, sequence memory, and natural language learning. He had temporal lobe epilepsy as a child. 
 Retrospective diagnosis
The following people were not diagnosed with epilepsy during their lifetime. A retrospective diagnosis is speculative and, as detailed below, can be wrong.
Name Life Comments Reference
Socrates 470–399 BC Ancient Greek philosopher. It is speculated that his daimonion was a simple partial seizure and that he had temporal lobe epilepsy. 
British television presenter Jill Dando. Has epilepsy and mental health problems.
Katie HopJulius Caesar 100–44 BC Roman military and political leader. He had four documented episodes of what were probably complex partial seizures. He may additionally have had absence seizures in his youth. There is family history of epilepsy amongst his ancestors and descendants. The earliest accounts of these seizures were made by the biographer Suetonius who was born after Caesar's death. 
Elizabeth Monroe 1768–1830 The wife of James Monroe, fifth President of the United States. Some historians believe her illness was epilepsy. She is reported to have been prone toconvulsions and was once seriously burnt after falling into a fireplace. 
Napoleon I of France 1769–1821 French military leader and emperor. A paper by William Osler in 1903 stated, "The slow pulse of Napoleon rests upon tradition; it has been suggested that his epilepsy and attacks of apathy may have been associated features in a chronic form of Stokes-Adams disease", which implies the seizures were not epileptic in origin. However, in 2003, John Hughes concluded that Napoleon had both psychogenic attacks due to stress and epileptic seizures due to chronic uremia from a severe urethral stricture caused by gonorrhea. 
Harriet Tubman 1820-22 – 1913 An African-American abolitionist. Developed what was probably epilepsy as a result of a head injury. 
George Gershwin 1898–1937 American composer. The first symptoms of his glioblastoma multiforme tumor were probably olfactory-uncinate simple partial seizures. He noticed the smell of burnt rubber at the same time as dizziness or, occasionally, brief blackouts. His condition deteriorated and he died six months later, despite surgery to remove the tumor. 
Philip K. Dick 1928–1982 A science fiction writer. One biographer suggests temporal lobe epilepsy as a possible cause of his visions, but also regards such speculation as futile and unverifiable.