The Public Service Enterprise Group (PSEG) is a publicly traded diversified energy company headquartered in Newark, New Jersey and was established in 1985.

The company's largest subsidiary is Public Service Electric and Gas Company (PSE&G). The Public Service Electric and Gas Company is a regulated gas and electric utility company serving the state of New Jersey and it is New Jersey's oldest and largest investor owned utility company; the Public Service Electric and Gas Company was established in 1928 and was originally a subsidiary of the New Jersey based Public Service Corporation.

The Public Service Enterprise Group (PSEG) was established in 1985 to take control of the Public Service Electric and Gas Company (PSE&G).

In 1989, Public Service Enterprise Group establishes the Enterprise Diversified Holdings Inc.(now PSEG Energy Holdings) to begin consolidation of unregulated businesses. In 2000, Public Service Enterprise Group split PSE&G subsidiary's unregulated national power generation assets to form PSEG Power, while the PSE&G subsidiary continued operating in New Jersey as a regulated gas and electric delivery company.

In June 2005, the acquisition of PSEG by Exelon, a Chicago and Philadelphia based utility conglomerate, was approved by the Federal Energy Regulatory Commission; however, the deal was never consummated and eventually dissolved after it became clear that it would not win state regulatory approval from the New Jersey Board of Public Utilities.

In 2009, PSEG began installing solar panels on 200,000 utility poles in its service area in a project costing $773 million, the largest such project in the world. The Solar 4 All project increased the capacity for renewable energy in New Jersey and was completed in 2013. In addition, PSEG is building four solar farms in Edison, Hamilton, Linden, and Trenton.

The Public Service Electric and Gas Company, commonly referred to as PSE&G, is the primary subsidiary of the Public Service Enterprise Group (PSEG).

PSE&G was established in 1928 as a subsidiary of the Public Service Corporation; the Public Service Corporation was formed in 1903 by combining more than 400 gas, electric and transportation companies in New Jersey. The parent Public Service Corporation was dissolved in 1948 and PSE&G became an independent company.

PSE&G sold its transportation operations to New Jersey Transit in 1980, leaving PSE&G exclusively in the utility business.

In 1985, PSE&G was purchased by the Public Service Enterprise Group.

Public Service Enterprise Group has three operating subsidiaries:

PSE&G serves the population in an area consisting of a 2,600-square-mile (6,700 km) diagonal corridor across the state from Bergen to Gloucester Counties. PSE&G is the largest provider of gas and electric service, servicing 1.8 million gas customers and 2.2 million electric customers in more than 300 urban, suburban and rural communities, including New Jersey's six largest cities.

PSEG Nuclear operates three nuclear reactors at two facilities in Lower Alloways Creek Township. PSEG owns one reactor at Hope Creek Nuclear Generating Station and operates two reactors at Salem Nuclear Power Plant where PSEG Nuclear holds a 57 percent stake (in partnership with Exelon Corporation). Exelon also operates two reactors at Peach Bottom Nuclear Generating Station in a 50/50 joint venture with PSEG.

PSEG Long Island provides electricity to 1.1 million customers in Nassau and Suffolk counties, and the Rockaway Peninsula of Queens, part of New York City. This system operates under an agreement with the Long Island Power Authority, the state agency that owns the system, that went into effect January 1, 2014. PSEG was selected to essentially privatize LIPA, taking over near complete control of the system including its brand name, whereas before this agreement only a number of functions were performed by the private sector and the system was operated under the LIPA name.

PSEG's transmission line voltages are 500,000 volts, 345,000 volts, 230,000 volts and 138,000 volts with interconnections to utilities in Pennsylvania, Delaware, and New York. The company's subtransmission voltages are 69,000 volts and 26,000 volts. PSEG's distribution voltages are 13,000 volts and 4,160 volts.

In 2001, PSEG received The Walter B. Jones Memorial and NOAA Excellence Awards in Coastal and Ocean Resource Management in the category of Excellence in Business Leadership for its Estuary Enhancement Program.

Researchers at the University of Massachusetts Amherst have identified PSEG as the 48th-largest corporate producer of air pollution in the United States, with roughly five million pounds of toxic chemicals released annually into the air. Major pollutants indicated by the study include manganese, chromium and nickel salts; sulfuric and hydrochloric acid.