Louis “Lou” Graydon Sullivan (June 16, 1951 – March 2, 1991) author, activist gay trans man. One of the first transgender men to publicly identify as gay, Lou is credited for the modern understanding of sexual orientation and gender identity as distinct, unrelated concepts.

Lou grew up in Milwaukee, Wisconsin, the third of six in a very religious Catholic family. As a ten-year-old, Lou began journaling his gender confusion and incongruence since his earliest memories. During his adolescence he expressed continued confusion, writing at age 15, "I want to look like what I am but don’t know what someone like me looks like. I mean, when people look at me I want them to think—there’s one of those people that has their own interpretation of happiness. That’s what I am."

By the age of 24, he left for San Francisco seeking "more understanding" and transition. Lou says that his family was supportive of the move and gave him "a handsome man's suit and his grandfather's pocket watch" as going-away presents.

Sullivan lived as an out gay man, but was repeatedly denied affirming surgery because he was gay, but by 1979, was finally able to find doctors and therapists who supported his starting testosterone. Sullivan had a double mastectomy surgery following a year later. He got a job as an engineering technician at the Atlantic-Ritchfield Company and was accepted in his new identity as a man with new co-workers.

In 1986, Sullivan obtained bottom surgery, but was diagnosed as HIV positive shortly after his surgery, and told he only had 10 months to live. He wrote, "I took a certain pleasure in informing the gender clinic that even though their program told me I could not live as a Gay man, it looks like I’m going to die like one."
Sullivan died of AIDS-related complications on March 2, 1991.