In 1941, he married Muriel Marshall (d. 2006). They had three sons who all graduated from Brooklyn Law School too: Jeremy Weinstein, a New York Supreme Court justice, Jonathan Weinstein, and Peter Weinstein, a Circuit Court judge in Broward County, Fla.
He was a member from Queens County of the New York State Assembly from 1959 to 1969, was majority leader from 1965 to 1968, and was chosen Speaker for the remainder of the term after the resignation of Anthony J. Travia in the middle of the year.
In August 1968, Weinstein, who as Speaker was fourth in line for the governorship, became Acting Governor for 10 days when Governor Nelson A. Rockefeller, Lt. Gov. Malcolm Wilson and Senate Majority Leader Earl W. Brydges went to the Republican National Convention in Miami Beach, Florida.
Weinstein was an ally of Mayor of New York Robert F. Wagner in the early 1960s and had a good relationship with Governor Rockefeller. Weinstein sponsored measures that created the Urban Development Corporation and the Crime Victims Compensation Board, reformed divorce and welfare laws, established a consumer bill of rights, increased aid for air-pollution controls and Regents scholarships, and promoted hospital expansion. He supported rent controls, veterans rights, aid to small businesses and antidiscrimination laws.
In 1969, he was elected to a 14-year term as a New York State Supreme Court justice in Queens. In a 1973 case, acknowledging he might be violating the law, he vacated the three-year term of a woman convicted of selling drugs, noting that she had terminal cancer and less than a year to live.
In 1980, he was appointed to the New York Supreme Court, Appellate Division, Second Department, with jurisdiction over Queens, Brooklyn, Staten Island and seven suburban counties. He participated in rulings that threw out unjust convictions, invalidated school financing based on property taxes and decided many other controversies. He left the bench in 1989 after reaching the mandatory retirement age.
He died at the Memorial Hospital in Pembroke Pines, Fla.