In 2010, he was convicted by a jury of two counts of criminal mischief for attacking a New York Post photographer, damaging his camera and car door, and breaking his finger.

[7][8] In 2001, Parker ran unsuccessfully in the New York City Council District 45 Democratic primary, coming in fifth with 14.95% of the vote.

[9] In 2002, Parker defeated former City Councilman Noach Dear in a tightly-contested Democratic primary for a newly drawn, open State Senate seat in Brooklyn.

[11] In the 2008 Democratic primary, Parker held off a strong challenge from New York City Councilmembers Simcha Felder and Kendall Stewart.

[17] After Democrats won the Senate majority in the 2018 elections, Parker was named Chair of the Committee on Energy and Telecommunications.

[22] A Parker-sponsored bill that barred utility companies from shutting off customers' service during the COVID-19 pandemic and other states of emergency was signed into law on June 17, 2020.

[23] On October 14, 2020, a Parker-sponsored bill recognizing Juneteenth (June 19) as an official state holiday was enacted, commemorating the day when the news of liberation came to Texas more than two years after President Abraham Lincoln’s Emancipation Proclamation went into effect.

[30] Parker is notable for what City & State NY referred to in 2019 as his "long history of making explosive remarks and getting involved in scuffles".

[32][40] She alleged that he pushed her during an argument, choked her, knocked her eyeglasses off her face, and then intentionally smashed her glasses by stomping on them.

[33][43][31][44] Parker was taken to the 67th Police Precinct station, booked, charged with a felony due to the value of damage to the camera and car door, and released without bail.

"[39] Parker was restrained by colleagues during a profane tirade against Senator Diane Savino in February 2010,[31] in which he referred to her as a "bitch".

[54] In April 2010, Parker launched into a tirade while white colleague, Republican Senator John DeFrancisco of Syracuse, was questioning a Black nominee for the New York State Power Authority at a confirmation hearing.

[56] "Amid the nearly two-minute tirade, committee chairman Carl Kruger told Parker he would be removed from the hearing room if he didn't settle down".

[61] His fellow Democrat, then-Senator Rubén Díaz Sr., himself a member of a racial minority group, opined that Parker "needs help".

"[64][65] Incoming Senate Majority Leader Andrea Stewart-Cousins expressed her "disappointment" at Parker's action, and then-lieutenant governor Kathy Hochul said it was "wildly inappropriate".