Zichal grew up in Elkader, Iowa, with parents Ken (a family physician) and Fran (CEO of Central Community Hospital) and a younger brother Ernie. She graduated from Central Elkader High School in 1994. She attended Cook College at Rutgers University, where she studied environmental policy and graduated in 1999.
While at Rutgers she had interned at the state chapter of the Sierra Club and was part of a panel interviewing candidates for U.S. House of Representatives in New Jersey's 12th congressional district. The support of environmentalists helped Democrat Rush D. Holt, Jr. stage an upset victory over Republican incumbent Michael J. Pappas. Holt hired Zichal and she went to Washington, D.C., where she served as a legislative director for him. She held the same position for Representative Frank Pallone from 2001 to 2002. She then was a legislative assistant and later director for U.S. Senator John Kerry from 2002 to 2008. She also worked as an assistant for the Senate Small Business and Entrepreneurship Committee. In these positions she worked on legislation to address climate change, reduce the country's dependence on oil for energy, and to protect American natural resources.
Zichal also served as a top advisor on energy and environmental issues to the 2004 Kerry presidential campaign and the 2008 Obama presidential campaign. She had first met Obama when he was lost in one of the Senate buildings and asked her for directions.
After serving on the Obama-Biden Transition Project in its Energy and Environment Policy Working Group, she was named to be Deputy Assistant to the President for Energy and Climate Change in December 2008, to serve as deputy to Carol Browner, who was named director of the White House Office of Energy and Climate Change Policy (as such, Browner's position was also informally referred to as the "Climate Czar" or "Energy Czar"). Zichal took office in January 2009. She was part of the administration response to the 2010 BP oil spill and supervised later modifications of safety standards for offshore oil and natural gas extraction.
When Browner left the White House in March 2011, Zichal took over the general responsibilities of coordinating the administration's energy and climate policy, now operating from within the U.S. Domestic Policy Council (the "czar" position itself having been reorganized away by the White House and its funding subsequently abolished by Congress in the mid-April 2011 federal spending agreement that averted a possible government shutdown). As such she became one of the White House staff members tasked with implementation of the Presidential Climate Action Plan. Her job also involved outreach activities towards the energy industry and environmentalists as well as dealing with Congress. With Republicans having taken over the House of Representatives following the 2010 midterm elections, chances of the large-scale climate and energy legislation passing that Browner had worked towards were essentially nil. At first the administration pursued more modest goals that could attract bipartisan support, such as reducing oil imports and promoting clean or renewable energy sources. The White House subsequently gave credit to Zichal for putting into place policy changes that would lead to a doubling of wind and solar power generation.
During the early portion of Obama's second term, Zichal was one of the public faces of the administration's approach of addressing climate change via federal regulatory action. She was the architect of a June 2013 plan to reduce greenhouse gases resulting from the nation's power plants by having the Environmental Protection Agency issue revised standards for carbon emissions from new and existing plants. They were the first ever such restrictions. (This plan eventually became known as the Clean Power Plan when issued in revised form in 2015; Zichal was still considered one of its architects. It became politically controversial during the 2016 U.S. presidential election, with opponents deriding it as the "War on Coal". Its implementation was blocked while challenges to it were made in U.S. federal courts.)
A 2013 profile from National Journal described her as having "developed a reputation among players across the energy spectrum as a smart, pragmatic, and serious player." A Democratic political operative and energy industry lobbyist called Zichal a "skilled communicator and negotiator" and said she was "dogged in her pursuit of gaining consensus with external stakeholders and delivering on a clean energy agenda for this administration." However, former Vice President and ardent environmentalist Al Gore complained in mid-2013 that the administration was not giving climate change sufficient priority, and making reference to Zichal said, "He does not yet have a team in the White House to help him implement solutions to the climate crisis. He hasn't staffed up for it ... he's got one person who hasn't been given that much authority."
In October 2013, Zichal announced that she would soon be stepping down from her post. She was given the chance to accept other positions within the administration, but declined. She was one of the last of Obama's 2008 campaign advisors to still be in the administration; she had been high valued inside the administration and by one report Obama had personally urged her to stay. Her last day was November 8, 2013, and she was succeeded by Dan Utech.
Zichal subsequently became an independent energy consultant, working at her own firm called Zichal Inc. In January 2015 she was named a senior fellow at the Atlantic Council. There she is part of the council's Global Energy Center. She remained active in the public debate over climate change and energy policy.