"PlayStation Network and some other gaming services were attacked over the holidays with artificially high levels of traffic designed to disrupt connectivity and online gameplay," Catherine Jensen, vice president of consumer experience for Sony's California-based US division, said in a blog post late Saturday.
"PlayStation Network is back online," she added.
Meanwhile all except three of Xbox's applications have been up and running since Friday.
Hacker group Lizard Squad took credit for the disruption and has targeted Sony in the past.
Sony had earlier this month been hit by another hacking attack that stole massive amounts of data from its servers.
The US has blamed North Korea for the attack.
However, a direct connection between the Sony PlayStation and Sony Pictures attacks is unlikely.