[1] Barnes was born in San Francisco, California, but grew up primarily in Edison, New Jersey.
[7] On November 5, 2013, he was elected to the State Senate, succeeding Barbara Buono who was running for Governor.
In one of the closest Senate races in the state, Barnes defeated Democrat-turned-Republican East Brunswick mayor David Stahl by a 4% margin.
[9] Barnes died from cancer at Robert Wood Johnson University Hospital in New Brunswick on February 22, 2021, at age 64.
[2][5] On August 10, 2021, the Dismal Swamp, located in Middlesex County, New Jersey, was renamed as the Peter J. Barnes III Wildlife Preserve.