Heng-Lehtinen was a member of Queer Alliance at Brown University. While attending Brown, he produced the documentary,
Free Within These Walls, about
Cuban
prisoners of conscience. Heng-Lehtinen was a field organizer for the
National Gay and Lesbian Task Force. He was later the membership director at Gender Justice LA, a grassroots organization that works to build the power of the transgender community in Los Angeles through
community organizing and leadership development. He also worked in fundraising at
Liberty Hill Foundation, organized a transgender leadership development conference with the
Transgender Law Center, and served as the membership manager at
GLAAD, an LGBTQ media advocacy organization. In May 2015, Heng-Lehtinen was honored by the LGBTQ-rights group,
SAVE Dade, at its 2015 Champions of Equality reception. He was honored for appearing with his mother in a highly rated television interview, increasing visibility of the transgender community. In May 2016, Heng-Lehtinen and his parents appeared in a
public service announcement titled "Family is Everything", which discusses his family's personal journey and acceptance, that all
South Florida families should embrace their children, and the reason why all Americans should have the same opportunities regardless of gender identity or sexual orientation. Heng-Lehtinen was the public education director at Freedom For All Americans, the national campaign for LGBTQ nondiscrimination protections. Heng-Lehtinen became deputy executive director for policy and action at the
National Center for Transgender Equality on July 1, 2019. In July of 2021 Heng-Lehtinen moved from Deputy Executive Director into his current role as executive director of the National Center for Transgender Equality. In 2022, Heng-Lehtinen appeared in
The Daily Wire documentary
What Is a Woman?, during which he talked about the issue of
transgender people in sports. In January 2024, NCTE revealed plans to merge with the Transgender Legal Defense and Education Fund (TLDEF), an organization dedicated to advancing transgender rights through legal action. The merger is expected to be completed in the summer 2024, resulting in the formation of a new entity called Advocates for Trans Equality (A4TE), with Heng-Lehtinen continuing in the role of Executive Director. ==Personal life==