[2] She founded Ingersoll Gender Center in Seattle in 1977, making it the oldest non-profit organization working in the space of transgender rights.
[9] Over the course of the late-20th century, Botzer made over 100 trips accompanying transgender residents of Seattle to Trinidad, Colorado where they sought gender reassignment surgery.
[9] In the late 1980s, Botzer witnessed an increase in clients of the center who were assigned female at birth and sought a masculinizing medical transition.
[11] In a 2018 interview with the South Seattle Emerald, Botzer said that just over a decade after founding Ingersoll Gender Center, she felt the community she had worked to build had reached a solid foundation and she had the confidence to focus her efforts more on political and social change.
[5][15] Having already worked on a national and international level, Botzer first gained a formalized role in local Seattle politics in 2015 when she was appointed to a task force under Mayor Ed Murray centered on LGBTQ issues.
[20] Throughout the 1990s and early 21st Century Botzer has served on the boards of many organizations working in the space of human rights related to gender identity and sexuality.
[5][21] In 2003, shortly following the Supreme Court of the United States made the decision to strike down anti-sodomy laws, Botzer worked via the Pride Foundation advocating on behalf of employees of Walmart to include discrimination on the basis of homosexuality to the company's anti-discrimination policy.
[22][14] Botzer co-authored a research paper published in the International Journal of Transgender Health in 2010 that proposes changes to the DSM-5 for diagnoses related to transgenderism.
[26] The drew figures to attend from more than a dozen countries, and among them was Marsha Botzer and then Mayor of Seattle Ed Murray, an openly gay man.
[27] Botzer received gender confirming surgery in 1981 from Dr. Stanley Biber, the top surgical provider for the transexual community in the United States at the time.