The series, which sets its focus on a group of Chicago EMTs, received a 13-episode order for its second outing, the network announced Thursday.
The British import is produced by Fox Television Studios. Bob Fisher ("Wedding Crashers") serves as an executive producer alongside Leary, who previously tackled the firefighter world in a dramatic fashion over on FX's "Rescue Me," which ran from 2004 to 2011.
The first season of "Sirens" averaged a modest but consistent audience on the NBCUniversal-owned cable network, averaging 1.6 million total viewers and 870,000 among adults 25-54.
“'Sirens' resonated with a broad fan base, and we are excited to grow this new audience further, as Season 2 promises a lot more laughs and irreverent humor,” said USA Network President Chris McCumber in a statement. “We’re pleased to continue our partnership with Denis Leary and Bob Fisher, whose unique brand of witty, off-kilter and laugh-out-loud writing is brought to life by the immensely talented cast."
It comes as the network sets its sights on bolstering its comedy game following its acquisition of "Modern Family" repeats, which rolled out on the network in 2013. The network recently launched its second original comedy, "Playing House" from Jessica St. Clair and Lennon Parham -- whose ratings have been unimpressive. Next on deck is "Benched," starring Eliza Coupe.