Activism, legal issues
Hannah, an active environmentalist, created her own weekly video blog called DHLoveLife on sustainable solutions. She is often the sound recordist, camera person and on-screen host for the blog. As of 2006, her home—which was built with green materials—ran on solar power, and she drove a car that ran on biodiesel. She has been vegetarian since age 11, and later became vegan. In late 2006, she volunteered to act as a judge for Treehugger.com's "Convenient Truths" contest. On December 4, 2008, Hannah joined Sea Shepherd Conservation Society's crew aboard the MY Steve Irwin as part of Operation Musashi.
On June 13, 2006, Hannah was arrested, along with actor Taran Noah Smith, for her involvement with over 350 farmers, their families and supporters, confronting authorities trying to bulldoze the largest urban farm in the U.S., located in South Central Los Angeles. She chained herself to a walnut tree at the South Central Farm for three weeks to protest against the farmers' eviction by the property's new owner, Ralph Horowitz. The farm had been established in the wake of the 1992 L.A. riots to allow people in the city to grow food for themselves. Horowitz, who had paid $5 million for it, sought to evict the farmers to build a warehouse. He had asked for $16 million to sell it but turned down the offer when the activists raised that amount after the established deadline. Hannah was interviewed via cell phone shortly before she was arrested, along with 44 other protesters, and said that she and the others were doing the "morally right thing". She was released from Century Regional Detention Center after several hours.
Hannah has worked to help end sexual slavery and has traveled around the world to make a documentary.
Hannah was among 31 people arrested on June 23, 2009, in a protest against mountaintop removal in southern West Virginia, part of a wider campaign to stop the practice in the region. The protesters, who included NASA climate scientist James E. Hansen, were charged with obstructing officers and impeding traffic after they sat in the middle of State Route 3 outside Massey Energy's Goals Coal preparation plant, The Charleston Gazette reported. In a Democracy Now! phone interview in June 2009, Hannah spoke briefly on why she went to West Virginia and risked arrest.
Hannah was arrested on August 30, 2011, in front of the White House as part of a sit-in to protest against the proposed Keystone oil pipeline from Alberta to the U.S. Gulf Coast. In a Huffington Post piece co-authored with Phil Radford, Hannah explained that the purpose of her action was to "shine the light" on President Obama's decision on the pipeline for "millions of voters" to see. In October 2011, Hannah and other pipeline opponents rode horses and bicycles and walked from the Pine Ridge Indian Reservation to the Rosebud Reservation to protest the project.
Hannah was the executive producer of Greedy Lying Bastards, a 2012 documentary against climate change denial.
In September 2012, Hannah signed environmental activist Tom Weis' open letter calling on President Barack Obama and Governor Mitt Romney to withdraw their support for the construction of the southern leg of the Keystone XL pipeline, that would transport oil sands from Montana to Texas. Other signatories included climate scientist James Hansen and actors Sheryl Lee, Mariel Hemingway, and Ed Begley Jr.
In October 2012, Hannah was arrested and jailed in Wood County, Texas, for criminal trespassing. She and a local landowner, 78-year-old Eleanor Fairchild, were arrested while protesting against the TransCanada Keystone XL oil sands pipeline by attempting to block heavy construction equipment. Although they were charged with trespassing, they were in fact protesting on Fairchild's land.
On February 13, 2013, Hannah was arrested at the White House along with Robert F. Kennedy Jr. and Conor Kennedy during a climate change protest against the proposed Keystone Pipeline.
On April 26, 2014, in Washington, Hannah and Neil Young led a march by the "Cowboy and Indian Alliance" group against the Obama administration to reject the proposed Keystone Pipeline.
Hannah endorsed Senator Bernie Sanders for president in the 2016 U.S. presidential election.
She is a member of the World Future Council, and a patron of The Gorilla Organization, a UK-based charity working to protect mountain gorillas.
On March 2, 2025, she introduced herself at the 97th Academy Awards ceremony with the phrase "Slava Ukraini," proclaiming her support for the Ukrainian cause amid the Russo-Ukrainian War.
