A British man has been arrested by officers from the new National Crime Agency under the Computer Misuse act.
NCA spokesman Andy Archibald said: "This arrest is the culmination of close joint working by the NCA, Police Scotland and our international partners.
Over the 12 months, Love and three unnamed co-conspirators living in Sweden and Australia allegedly planted malware on government computers in order to steal data, according to an indictment filed in District Court in New Jersey.
"Cyber-criminals should be aware that no matter where in the world you commit cyber crime, even from remote places, you can and will be identified and held accountable for your actions.
"The NCA has well-developed law enforcement alliances globally and we will pursue and deal robustly with cyber-criminals."
They are alleged to have obtained personal information of more than 4,000 employees for the Missile Defense Agency and "numerous" NASA employees, according to the indictment. The group allegedly publicised their attacks on Twitter.
Government databases were attacked using SQL injection techniques. The attackers also gained access to government computers by exploiting vulnerabilities in ColdFusion, Adobe Systems' Web application development platform.
In an attempt to avoid detection, the group allegedly channeled its attacks through proxy servers and used TOR, a network that provides greater privacy by routing encrypted Web traffic through servers around the world.
The indictment alleges the attacks "collectively resulted in millions of dollars in damages to the government victims."
Under the Computer Misuse Act, individuals can be arrested for launching attacks from within the UK against computers anywhere in the world.
Neither of his co-conspirators have been charged in connection with the hacking.
An indictment served in a US court included pieces of instant message conversations that Love allegedly had with his partners.
In one, he is said to have written: "Ahaha, we owning lots of nasa sites."
In another exchange, he said "This ... stuff is really sensitive", according to prosecutors.
Love has been charged by US authorities, but only arrested by British investigators, the NCA confirmed.