Despite his family being loyal to Caesar, with Casca's brother Gaius Servilius Casca even being a close friend of Caesar's, both siblings joined in the assassination. Casca struck the first blow, attacking Caesar from behind and hitting his neck, after Tillius Cimber had distracted the dictator by grabbing his toga. The other assassins then joined in.
At the time Casca held the office of Tribune of the People. After the assassination he fled Rome, and his colleague in the tribunate, P. Titius, had him deprived of his office. Casca joined Marcus Junius Brutus and Gaius Cassius Longinus, the leaders of the assassins. He seems to have died, probably by suicide, in the aftermath of their defeat at the Battle of Philippi, in 42 B.C.
- He is called "envious Casca" by Mark Antony in William Shakespeare's play Julius Caesar (1599):
- "See what a rent the envious Casca made". This quote, in turn, became the title of a mystery novel by Georgette Heyer.
- In the 1953 film of Shakespeare's Julius Caesar, Casca is portrayed by Edmond O'Brien.
- In the 1963 film Cleopatra, Casca is portrayed by Carroll O'Connor.
- In the 1970 film of Shakespeare's Julius Caesar, Casca is portrayed by Robert Vaughn.
- In the TV series Rome (2005–07), Servilius Casca is portrayed by Peter Gevisser.
- John Hazel, Who's Who in Roman World, Routledge, 2002, p.55
- William George Smith, Dictionary of Greek and Roman Biography and Mythology: Abaeus-Dysponteus, p.618
- Wayne G. Sayles, Ancient Coin Collecting III: The Roman World-Politics and Propaganda, Krause Publications, 2007, p.16