A California man behind the website Silk Road, once a thriving online black market for the sale of heroin, cocaine, LSD and other drugs and illicit goods, was convicted on Wednesday of all seven counts related to the enterprise.

The verdict against the defendant, Ross W. Ulbricht, was delivered swiftly: Jurors began deliberating in the morning, and reported that they had reached a consensus about 3 1/2 hours later.

Prosecutors had portrayed Mr. Ulbricht, 30, as a “digital kingpin” who ran the website on a hidden part of the Internet, where deals could be made anonymously and without the scrutiny of law enforcement.

Evidence showed that Silk Road generated revenues of more than $213 million from January 2011 to October 2013, when Mr. Ulbricht was arrested by the Federal Bureau of Investigation in a library in San Francisco while he was logged on to his laptop as Dread Pirate Roberts, the pseudonym under which prosecutors said he operated the website. Deals were conducted in Bitcoins, and Mr. Ulbricht took millions of dollars in commissions, the government said.