Krolikowski claims the school branded him "worse than gay" and fired him after he revealed he was transgender, the Daily News has reported.
His termination has resulted in an outcry of mass indignation and wave of public support, including a "Support Mr. K" Facebook group with about 2,000 members, and a petition that has attracted around the same number of signatures.
Krolikowski, who was born a man but dresses as a woman and identifies as transgender, told BI he still prefers to use male pronouns since his students call him "Mr. K."
Two SFP alumni told Business Insider they're steadfast in their support for the teacher.
Christopher Siess, founder of the St. Francis Prep alumni Facebook page, studied Human Love and Sexuality under Mr. K in 2007 and never had any qualms with his teacher's mannerisms. When asked if he ever suspected his teacher was transgender, Christopher replied, "Transgender, no -- effeminate, yes. But by no means is he worse than gay, whatever that means. He's one of the top five teachers I've ever had."
Cristina Guarino, who took Mr. K's Human Love and Sexuality class in 2008, started the petition that asks the school to "formally apologize to a loved and well-respected former member of their staff." Though incensed at what she considers to be a disgusting display of discrimination, Cristina takes solace in knowing that "at least he'll see the staggering numbers of people who support him."
When Business Insider spoke with Mr. K last night, he was reluctant to divulge any information without the advice of his lawyer. He did, however, appear humbled by the public response and took the time to thank his many supporters, including Cristina. "I'm so overwhelmed," he said, "Thank her for me ... I appreciate all the effort and I think it's really going to help."
Krolikowski says in 2011 he informed Principal Brother Leonard Conway that he was transgender and that he would start coming to class dressed as a woman, ABC News has reported. While he previously wore suits to school, he also says he wore earrings and manicured his nails in a "feminine style."
He claims Conway told him that being transgender was "worse than gay" and barred him from attending public events at the Catholic school if dressed in feminine apparel.
The teacher says that he toned down his appearance and received excellent reviews over the next year, but nonetheless was accused of insubordination in June of 2012, and fired two months later.
Business Insider also reached out to St. Francis, and the school declined to comment.