In recent years, Hollywood has become much better at hunting pirates. Just last week, five men were convicted of operating Jetflicks, an illegal streaming site that federal prosecutors said offered a stolen lineup of TV shows and movies that was larger than the combined catalogs of Netflix, Hulu and Amazon’s Prime Video.

But thieves are also getting better, moving operations overseas and taking advantage of the rising popularity of streaming to steal more content.

So entertainment companies — already under pressure from Wall Street to improve streaming economics — are intensifying their antipiracy efforts, hiring a former F.B.I. official to lead the drive and renewing a push for federal legislation to combat online thievery overseas. The companies, which include Netflix, Disney, NBCUniversal and Warner Bros. Discovery, are also expanding their piracy policing to include live sports.

On Monday, the Motion Picture Association, a trade group that represents those companies and others, said it had hired Larissa L. Knapp, a 27-year veteran of the F.B.I., as its top pirate chaser. In her time at the bureau, Ms. Knapp served in senior positions in national security, counterterrorism, intelligence and cybersecurity. She got her start at the F.B.I. as a special agent investigating computer hacking and intellectual property crimes and ultimately became the bureau’s fourth-highest-ranking official and highest-ranking woman.

Her formal title at the Motion Picture Association will be executive vice president and chief of global content protection. Ms. Knapp succeeds Jan van Voorn, a Dutch antipiracy expert who left in March to run IP House, a private-equity-backed start-up that focuses on copyright enforcement.

“Larissa’s relationships in law enforcement will be enormously helpful to us,” Charles H. Rivkin, the Motion Picture Association’s chairman and chief executive, said in an interview. “We’re a long way from guys on street corners selling counterfeit DVDs. This is global organized crime. The people stealing our movies and television shows are also involved with sex trafficking, money laundering — all the ills of society.”

The association’s antipiracy effort is known as ACE, which stands for the innocuous-sounding Alliance for Creativity and Entertainment. Started in 2017, ACE is a coalition of more than 50 media companies around the world. Before its creation, the Motion Picture Association was completing about a dozen antipiracy actions a year; it now executes a dozen or more actions a week. There were 1,400 illegal streaming sites in North America in 2019, according to Mr. Rivkin. The number is now closer to 200.

“ACE has been remarkably successful since its 2017 launch, but the battle against piracy continues,” Ms. Knapp said in an email. “The idea of working with an organization strong enough to take this on is extremely appealing to me.”

Fighting piracy overseas — particularly in Asia — remains arduous. MUSO, a piracy tracking firm, said in January that video sites stocked with stolen content attracted 141 billion visits worldwide in 2023, up 12 percent from 2019.

“The bad guys have left for other places where it is more difficult for us because the rule of law is not as strong,” Mr. Rivkin said. “The top three English-language piracy sites are all located in Vietnam.”

To that end, the Motion Picture Association has started to campaign on Capitol Hill for a new tool: court-mandated site blocking. Studios want a law that gives them the ability — under a process overseen by a federal judge — to force internet service providers to block access to overseas piracy sites. In recent years, more than 60 countries have adopted similar legislation, Mr. Rivkin said, adding, “It’s time for it to happen in America.”

Some entertainment companies see antipiracy efforts as a way to deliver growth. In countries like Spain and Mexico, for instance, ACE-facilitated shutdowns of piracy sites have resulted in tens of thousands of new customers for legitimate services.

Hollywood in some ways is still stinging from the 2012 failure of the more aggressive Stop Online Piracy Act, or SOPA, which was also aimed at overseas sites. The Motion Picture Association was badly beaten by Google and other technology companies, which argued that the legislation would, in effect, allow the government to censor the internet.

Since then, the proliferation of legitimate streaming services has made it easier for pirates to steal content. “They can take a movie on one of our streaming services in less than four seconds and upload it three seconds later,” Mr. Rivkin said.

How much resistance from tech lobbyists will the Motion Picture Association face this time? It’s unclear. Since the SOPA fight, Apple and Amazon have both moved into Hollywood, and Netflix has become a full-fledged member of the Motion Picture Association. While Apple TV+ and Amazon are not formal members, they are deeply involved with ACE.

One technology trade group has made its displeasure known: the Computer and Communications Industry Association, which counts Google and Meta — and Amazon and Apple — as members. At a congressional hearing in December, Matthew Schruers, president of that association, said there was “a long history of site-blocking injunctions leading to overreach.” He continued, “It is simply not possible to craft a uniquely American, speech-protecting site-blocking regime.”