For nearly 20 years Sarah Leen worked as an independent photographer for National Geographic magazine until 2004 when she joined the NGM staff as a Senior Photo Editor. In 2013, Leen became the first female Directory of Photography for National Geographic Magazine and Partners. As a photographer she published 16 National Geographic magazine stories, one book and produced five covers for NGM. She has won numerous awards for both her photography and photo editing from the Pictures of the Year and the World Press Photo Awards and the International Photography Awards.

Leen teaches visual storytelling and photo editing at the Eddie Adams and Missouri Photo workshops and her own Female Perspectives in Visual Storytelling. She has edited ten photobooks since 2020 including Ukraine: A War Crime, the POY Photobook of the Year in 2023, Ukraine Love + War, HABIBI by Antonio Facciolongo, We Cry in Silence by Smita Sharma the 2022 Lucie Book Award for Independent Book, The Phoenician Collapse by Diego Ibarra Sanchez, A Troubled Home by Anush Babajanyan and Cosmic Solitude by Yulia Grigorants.

Leen is the Co-Chair of the Board of the International League of Conservation Photographers, is a member of the Lucie Awards Board of Advisors and in 2024 she received an Honorary Doctorate of Humane Letters from her alma mater the University of Missouri School of Journalism. She is an Oskar Barnack Award nominator and participates on many juries and portfolio reviews.