[22][23] Hackettstown was incorporated as a town by an act of the New Jersey Legislature on March 9, 1853, from portions of Independence Township.

[26][27] Hackett is said to have "contributed liberally to the liquid refreshments on the christening of a new hotel, in order to secure the name which, before this, had been Helms' Mills or Musconetcong.

"[28][29] In 1886, Tillie Smith, a 19-year-old kitchen worker from a poverty-stricken family, was raped, murdered and left lying in an open field near the campus of the Centenary Collegiate Institute, where she worked.

[30][31] James Titus, a janitor at the school, was tried and convicted of the rape and murder, based on circumstantial evidence and public opinion shaped by yellow journalism.

Titus was sentenced to hang, but he signed a confession to avoid the death penalty and served 19 years of hard labor.

[32][33][34] The killing remains a popular local legend, inspiring several books, Weird NJ magazine articles,[35] theatrical performances and dark tourism ghost tours.

[38][39] In 1925, a train wreck just outside of town killed about 50 people and injured about 50 others en route to Hoboken, New Jersey, from Chicago.

[40][41][42] Fund-raising campaigns for a new hospital started as early as 1945, supported and organized by local civic and business groups including Kiwanis, Unico International, PTA and others, a large donation by the Seventh Day Adventists and a grant from the United States Public Health Service, the 106-bed Hackettstown Community Hospital was established in 1973.

[48] Hackettstown was named #72 of the top 100 towns in the United States to Live and Work In by Money Magazine in 2005; it has not been included since.

[52] Unincorporated communities, localities and place names located partially or completely within the town include Warren Furnace.

[53] Hackettstown borders the townships of Washington (Morris County) to the southeast, Mansfield to the southwest, Allamuchy to the north, Mount Olive to the northeast, and Independence to the west.

[69] Hackettstown operates under a mayor-council form of government that was created by a special charter adopted by the New Jersey Legislature and approved by the voters in 1970.

[6][78] The mayor is the town's chief executive officer, overseeing its day-to-day operation and presenting an annual budget.

[79] As of 2022[update], the mayor of Hackettstown is Republican Gerald DiMaio Jr. whose term of office ends December 31, 2023.

Members of the Town Council are Jody Becker (R, 2024), Matthew Engelau (R, 2022), Leonard Kunz (R, 2023), James Lambo (R, 2022; elected to serve an unexpired term), Scott Sheldon (R, 2024) and Eric Tynan (R, 2023).

[3][80][81][82][83] James Lambo was selected from a list of three candidates nominated by the Republican municipal committee to fill a vacant seat.

The seat, which expired in December 2018, was vacated by William Conforti in August 2016, after his announcement that he was moving out of the municipality.

[87][88][89] For the 119th United States Congress, New Jersey's 7th congressional district is represented by Thomas Kean Jr. (R, Westfield).

[96][97] Constitutional officers of Warren County are: Clerk Holly Mackey (R, Alpha; 2027),[98][99] Sheriff James McDonald Sr. (R, Phillipsburg; 2025)[100][101] and Surrogate Michael J. Doherty (R, Washington; 2025).

[105] Among the town's 2010 Census population, 55.6% (vs. 62.3% in Warren County) were registered to vote, including 69.8% of those ages 18 and over (vs. 81.5% countywide).

[122][123][124][125] Students from the townships of Allamuchy, Independence, and Liberty, attend the district's high school as part of sending/receiving relationships.

[130] Centenary University, a private college affiliated with the United Methodist Church, was founded in 1867 and received approval in 1995 to grant master's degrees.

The Hackettstown station is the western terminus of the NJ Transit Morristown Line and the Montclair-Boonton Line, which both provide service to Hoboken Terminal with connections to Pennsylvania Station in Midtown Manhattan via Midtown Direct trains.