With his Father, he co-founded the Paul Revere Society. In 1998, he ran as a Republican for the 6th district seat in the California State Assembly, receiving an endorsement from the President of the NAACP branch in Oakland, California. In June 1998, Weiner won the Republican primary election by five votes. Among his campaign issues included advocacy for Proposition 227, the ballot initiative eliminating bilingual education in public schools, and protection of old-growth forests. Receiving 13.3% of the vote, Weiner lost to incumbent Democrat Kerry Mazzoni. After he lost the election, election posters depicting him were vandalized in an anti-Semitic manner.
Weiner has also engaged in the real estate industry by buying and selling homes. In 2006, he bought the West Hollywood home of basketball player Carlos Boozer for $10 million. In 2008, he listed his home there for under $3 million (originally nearly $15 million based on replacement costs) and sold it for $8 million in 2009.
In 2009, Weiner donated $25,000 to the California gubernatorial campaign of Gavin Newsom, who was the Democratic mayor of San Francisco. Newsom returned the donation and Weiner gave it to charity.
In 2016, he entered the Forbes list of the 500 richest Americans at position 494, with an estimated worth of 3.4 billion dollars.