When Zwiener questioned RepublicanJason Isaac, who represented her district in the Texas House of Representatives, about his support for Texas Senate Bill 4, which effectively banned sanctuary cities in Texas, over Facebook, Isaac accused her of "trolling" and blocked her.[4] She decided to run for his seat in the Texas House and declared her candidacy in March 2017 for the Texas House of Representatives elections, 2018 and received assistance from Run for Something.[4] Zwiener was pregnant during the campaign and gave birth in summer of 2018.[5] She finished in second place to Rebecca Bell-Metereau in the Democratic Partyprimary election, but advanced to a runoff election and won by less than 200 votes.[6][7] Zwiener went into labor at an anti-Donald Trump protest, and continued to campaign from the hospital before and after giving birth. She won in the general election, receiving 51 percent of the vote,[5] defeating Republican nominee Ken Strange, who polled 49 percent of the ballots cast. She succeeded Isaac in the state House; Isaac did not seek reelection to the House but ran unsuccessfully for his party's nomination in Texas's 21st congressional district.[8]
Zwiener is bisexual and is one of the founding members of the first LGBTQ Caucus in the Texas Legislature. She is one of the authors of HB 517 which would ban conversion therapy in Texas.[9][10][11]
Zwiener also founded the Texas Energy and Climate Caucus, a bipartisan coalition of 56 members defending renewable energy and bringing more innovative, low-carbon energy to Texas.[12]
