Middlesex is governed under the Borough form of New Jersey municipal government.The governing body consists of a Mayor and a Borough Council comprising six council members, with all positions elected at-large on a partisan basis as part of the November general election.21.7% of all households were made up of individuals and 10.7% had someone living alone who was 65 years of age or older.The average household size was 2.71 and the average family size was 3.17. For every 100 females age 18 and over, there were 91.9 males.The Borough form of government used by Middlesex, the most common system used in the state, is a "weak mayor / strong council" government in which council members act as the legislative body with the mayor presiding at meetings and voting only in the event of a tie.The mayor can veto ordinances subject to an override by a two-thirds majority vote of the council.About 0.6% of families and 2.1% of the population were below the poverty line, including 1.6% of those under age 18 and 4.6% of those age 65 or over.).The racial makeup of the borough was 87.26% White, 3.36% African American, 0.13% Native American, 4.16% Asian, 0.02% Pacific Islander, 3.21% from other races, and 1.86% from two or more races.
The Borough Council consists of six members elected to serve three-year terms on a staggered basis, with two seats coming up for election each year in a three-year cycle.Members of the Middlesex Borough Council are Council President Robert Schueler (D, 2018), Patrick Corley (D, 2018), Kevin Dotey (D, 2016), John L.Madden (R, 2017), John "Jack" Mikolajczyk (R, 2017) and Daniel Parenti (D, 2019).In the borough the population was spread out with 24.1% under the age of 18, 6.2% from 18 to 24, 32.3% from 25 to 44, 23.2% from 45 to 64, and 14.2% who were 65 years of age or older. The median income for a household in the borough was $60,723, and the median income for a family was $70,343.
Males had a median income of $47,446 versus $34,232 for females. About 2.4% of families and 3.6% of the population were below the poverty line, including 4.1% of those under age 18 and 2.3% of those age 65 or over.
All legislative powers of the Borough are exercised by the Mayor and Council.