In a lopsided victory, the incumbent Sampson — who is accused of with stealing more than $400,000 in home foreclosure sales and tampering with an FBI investigation, among other charges — garnered 3,000 votes more than his closest challenger to take 54.2 percent of the vote in the Democratic primary for the 19th Senate district.
Union organizer Dell Smitherman picked up 29.9 percent of the vote.
Smitherman, who was endorsed by Mayor Bill de Blasio, called the loss a "disappointment," but said his race helped build "a foundation for change" in the community.
"From the very beginning, this campaign was never about one person or idea but, rather, the overarching belief that working families in Southern and Eastern Brooklyn deserve honest, progressive representation that works for us," read a statement from Smitherman.
Sean Henry, who focused some of his campaign on his own history of being a former homeless teen, came in third with 12.5 percent of the vote in the district, which also includes parts of Canarsie, Bergen Beach, Mill Basin and Sheepshead Bay.
Barron, meanwhile, defeated community activist Chris Banks in the Democratic primary for the 60th Assembly district by more than 1,000 votes, 63.2 percent to 36.8 percent.
The former councilman is running to replace his wife, Inez Barron, who last year won his term-limited seat on the City Council. The Assembly seat was one of five Albany seats in the borough that have been left vacant for months.