Mazzella graduated cum laude with a degree in law from the University of Naples in 1954.
On 29 June 2013 he was made vice president of the Court.
In 2009 Italian Prime Minister Silvio Berlusconi visited Mazzella at a dinner party at his house, with fellow Constitutional Court judge Paolo Maria Napolitano and Justice Minister Angelino Alfano was also present.
At the time an immunity bill which would also affect Berlusconi was under discussion in the Constitutional Court.
The gathering provoked outrage under political opponents.