Antonio Orlando, a suspected boss in the Camorra crime syndicate, was arrested after 15 years on the run.
While a fugitive, the 60-year-old continued to play a leading role in the clan, police said.
Authorities found Orlando in an apartment in the municipality of Mugnano, which featured a running treadmill, sauna and tanning machine.
Police also discovered a secret hideaway under the seat of the sauna.
The mobster had been preparing to move to another hideout and was in the process of destroying fake identity documents when police broke in.
According to regional commander Ubaldo del Monaco, Orlando “raised his hands in a sign of surrender” before being arrested.
Agents uncovered €6,000 in cash in the apartment along with messages received from clan members on the outside world.
The Camorra allegedly specialises in trafficking drugs from Morocco and Spain, as well as money laundering, and also has a history in extortion and murder.