Ross Ulbricht isn't spending his life behind bars without a fight.

The Silk Road mastermind, who last week was sentenced to life in prison for his role as the so-called "kingpin of a worldwide digital drug-trafficking enterprise," has appealed his sentence. According to court documents obtained by Motherboard, Ulbricht's lawyers filed the notice of appeal on Thursday, disputing the sentence and his earlier guilty conviction.

The report notes that it's unknown whether the appeals process will include new oral arguments, though Ulbricht will likely push for it given "how hard he argued for leniency."

U.S. Attorney Preet Bharara said Ulbricht was a "drug dealer and criminal profiteer who exploited people's addictions and contributed to the deaths of at least six young people," but not everyone thought the sentence matched the crime. Some argued that the life sentence was too harsh, including actor Russell Brand, who posted a passionate YouTube video (below) this week in defense of Ulbricht.

"In a way Ross Ulbricht is the American Dream," Brand said. "He's an entrepreneur. He saw a new market, he went for it."

"Is that any different from the genesis of Coca Cola or General Motors or Philip Morris? General Motors kill their customers, Philip Morris kill their customers Coca-Cola kill their customers and workers," Brand continued. "This guy is just an entrepreneur."

Ulbricht was facing a minimum of 20 years in prison on one of the counts after being convicted in February on charges of engaging in a continued criminal enterprise and distribution of narcotics on the Internet, each of which carried a potential life term. Prosecutors also alleged that he solicited the murders of people he saw as threats and that at least six deaths were caused by drugs purchased on Silk Road.