The 73-year-old will appear in the Zooey Deschanel comedy as an old drunk man who claims to be Nick (Jake Johnson) from the future.
Nick becomes unnerved when 'Older Nick' arrives at his bar and appears able to predict his future, according to TVLine.
Barry plays Arlo Givens on FX drama Justified and has also made recent appearances on CSI and The Closer.
Other guest stars announced for season two of New Girl include Parker Posey (The Good Wife), David Walton (Bent, Burlesque) and Niecy Nash (Reno 911!).
The series returns to Fox on Tuesday, September 25 at 8/7c. In the UK, the series airs on E4.
> Zooey Deschanel's New Girl adds The Office actor Nelson Franklin
Watch a promo for season two of New Girl below: