Oliver Stark is known for his activism, particularly in the areas of veganism, animal rights, and environmentalism. Here is a list of the stuff he did over the years:

SOURCE - In 2017, Fox and the show’s cast and crew have teamed up with the National Fallen Firefighters Foundation to raise money.
SOURCE - In 2019, he joined the Red Cross for their "Sound the Alarm" campaign.
SOURCE - In 2020, he took part in the "End the Horror of Live-Shackle Slaughter" campaign.
SOURCE - In 2021, he started working with a charity that provides workout equipment to firehouses to help real-life firefighters stay fit.
SOURCE - In 2021, he raised money for a charity that aims to support and empower individuals and communities affected by breast cancer.
SOURCE - In 2022, Oliver was a part of a group of ambassadors who joined Re:wild in LA to learn more about connecting with the wild and how we can all take the magic of rewilding into our own hands.
SOURCE - In 2023, he volunteered with Feeding America, largest hunger-relief organization in the United States.
SOURCE - In 2023, he was a part of the Writers Guild of America strike.
SOURCE - In 2024, he participated with Ryan Guzman, Aisha Hinds, Tracie Thoms, and Bryan Safi from 9-1-1 in Celebrity Family Feud, and they earned enough points to win the $25,000 for their charity of choice: the American Red Cross.
SOURCE - In 2025, he took part in the 2025 NBA All-Star charity event that focused on community impact and youth basketball in the San Francisco Bay Area.
SOURCE - In 2026, he took part in the one-night only fundraiser LOVE THY NEIGHBOR: A Twilight Zone Charity Live Script Reading.

He also uses social media to spread awareness or share opinions on various topics.
SOURCE - In 2019, he made use of Twitter to advocate for both the Black Lives Matter movement and the suicide prevention hotline.
SOURCE - In 2019, he showed support for transgender people.
SOURCE - In 2020, he spoke about the climate change.
SOURCE - In 2020, he talked about how bad the racial slurs are when used by the wrong people.
SOURCE - In 2021, he shared about St. Francis Center, a refuge for men and women who are homeless in the metro Denver area, providing services to help transition out of homelessness.
SOURCE - In 2021, he said that he doesn't feel uncomfortable to play queer character.
SOURCE - In 2024, Stark showcase his LGBTQIA+ allyship by issuing a statement in which he condemned the biphobes.
SOURCE - In 2024, posted a story about the bi-visibility day.
SOURCE - In 2024, he did an interview where he talked a lot about mental health awareness.
SOURCE - In 2025, he posted about how honored he is to play a bisexual character during Pride Month.
SOURCE - In 2025, he posted a story on Instagram for Bi Visibility Day.

This is what Oliver said in a interview for IANS: "For me, feminism is about opportunities being evenly distributed. So, everybody has the ability and the path ahead of them to rise. And anything I can do to help that… I want to put myself there and do my best. For me, it is very important. Because if you are lucky enough to be in the job that gives you some kind of platform (to speak up), I think you should use that platform for what you believe in. I count myself as a feminist. I’m a vegan, so I believe in animal rights. I stand behind the Black Lives Matter here in the US. I want to help wherever I can. The most important thing is to be fully educated on it before you speak out. Because you cannot just say things out. I think if it is something an actor believes in and has an opinion on it, then there is no better way to use that platform. People are becoming braver and are speaking up. They see that there is a community around them who will support them and power is being taken away from those who are against that movement."