Sullivan was born in Paterson, New Jersey. She is a 1969 graduate of William Howard Taft High School in the Woodland Hills district of Los Angeles, California. She was awarded a Bachelor of Science degree in Earth Sciences from the University of California, Santa Cruz in 1973, and a Ph.D. in Geology from Dalhousie University in 1978. While at Dalhousie, she participated in several oceanographic expeditions that studied the floors of the Atlantic and Pacific oceans.

Sullivan joined NASA in 1978 and was part of the first astronaut groups to include women. She performed the first extra-vehicular activity (EVA) by an American woman during Space Shuttle Challenger mission STS-41-G on October 11, 1984. Sullivan and mission specialist David Leestma performed a 3.5-hour spacewalk in which they operated a system designed to show that a satellite could be refueled in orbit. During their eight-day mission, the crew deployed the Earth Radiation Budget Satellite, conducted scientific observations of the earth with the OSTA-3 pallet (including the SIR-B radar, FILE, and MAPS experiments) and large format camera (LFC), conducted a satellite refueling demonstration using hydrazine fuel with the Orbital Refueling System (ORS), and conducted numerous in-cabin experiments as well as activating eight “Getaway Special” canisters. STS-41G completed 132 orbits of the Earth in 197.5 hours, before landing at Kennedy Space Center, Florida, on October 13, 1984.

In 1988, Sullivan joined the U.S. Naval Reserve as an oceanography officer, retiring with the rank of captain in 2006. She was stationed in Guam.

In April 1990, Sullivan served on the crew of STS-31, which launched from Kennedy Space Center, Florida, on April 24, 1990. During this five-day mission, crew members aboard the Space Shuttle Discovery deployed the Hubble Space Telescope, and conducted a variety of middeck experiments involving the study of protein crystal growth, polymer membrane processing, and the effects of weightlessness and magnetic fields on an ion arc. They also operated a variety of cameras, including the IMAX cargo bay camera, for earth observations from their record setting altitude of 380 miles. Following 76 orbits of the earth in 121 hours, STS-31 Discovery landed at Edwards Air Force Base, California, on April 29, 1990. In 1985, she became an Adjunct Professor of Geology at Rice University.

In 1991, Sullivan received the Haley Space Flight Award for “distinguished performance in the deployment of the Hubble Space Telescope on Mission STS-31 during April 1990.”

Sullivan left NASA in 1993. She flew on three space shuttle missions and logged 532 hours in space.

In 1993, Kathryn Sullivan received the Gold Medal of the Society of Woman Geographers, for being the first American woman to walk in space, during the 1984 Space Shuttle Challenger mission. She took a pennant bearing the insignia of the Society with her on that mission.

In 1994, Sullivan received the Golden Plate Award of the American Academy of Achievement.

After leaving NASA, Sullivan served as chief scientist of the National Oceanic and Atmospheric Administration (NOAA). In 1996 she was named president and CEO of the COSI Columbus, an interactive science center in Columbus, Ohio. From 2006 to 2011 she was Director for Ohio State University’s Battelle Center for Mathematics and Science Education Policy as well as a volunteer science advisor to COSI. Under her leadership, COSI strengthened its impact on science teaching in the classroom and its national reputation as an innovator of hands-on, inquiry-based science learning resources. She was appointed to the National Science Board by President George W. Bush in 2004.

In 2004, Sullivan was inducted into the Astronaut Hall of Fame and received the Adler Planetarium Women in Space Science Award.

In 2009, Sullivan was elected to a three-year term as the chair of the Section on General Interest in Science and Engineering for the American Association for the Advancement of Science.

In January 2011, the White House sent to the Senate the nomination of Sullivan by President Barack Obama to be an assistant secretary of commerce. Sullivan was first nominated in December 2010, but because the Senate did not approve her nomination and a bevy of others forwarded late in December, the White House renewed the formal requests.

On May 4, 2011, Sullivan was confirmed by unanimous consent of the U.S. Senate and appointed by President Obama to serve as Assistant Secretary of Commerce for Environmental Observation and Prediction and Deputy Administrator for the National Oceanic and Atmospheric Administration.

Sullivan became Acting Under Secretary of Commerce for Oceans and Atmosphere and Acting NOAA Administrator on February 28, 2013, following the resignation of Jane Lubchenco.

President Obama nominated Sullivan to serve as the Under Secretary of Commerce for Oceans and Atmosphere and NOAA Administrator on August 1, 2013 and she was confirmed by the Senate on March 6, 2014.

In 2013, Sullivan was awarded an honorary doctorate of Science from Willamette University in conjunction with her presentation of a commencement address.

In 2014, Sullivan was honored in the Time 100 list. According to John Glenn, “Kathy is not just an ivory-tower scientist. She was part of NASA’s first class of female astronauts, selected in 1978, and went on to fly three shuttle missions. She is the first American woman to walk in space and served aboard the mission that deployed the Hubble Space Telescope. That role in helping humanity look outward has not prevented her from looking homeward. The planet is suffering increasingly severe upheavals, at least partly a result of climate change — droughts, floods, typhoons, tornadoes. I believe my good friend Kathy is the right person for the right job at the right time.”

In May 2015, Sullivan was awarded an honorary doctorate from Brown University for her “abundant contributions to science, education and the public good, and her ongoing commitment to improving the state of our planet for future generations.”

In September 2015, Sullivan presented the John H. Glenn Lecture in Space History Series at the Smithsonian National Air and Space Museum in Washington, D.C. Titled “Looking at Earth: An Astronaut’s Journey,” Sullivan discussed her life of exploration and discovery, what it’s like to fulfill her childhood dreams, and how NOAA’s study of our planet helps us understand today’s environmental challenges.

She was elected to the National Academy of Engineering in 2017 and to the American Academy of Arts and Sciences in 2017.

In November 2019, Sullivan’s book Handprints on Hubble: An Astronaut’s Story of Invention was released from MIT Press. ‘’Handprints on Hubble’’ recounts Sullivan’s experience as part of the team that launched, rescued, repaired, and maintained the Hubble Space Telescope. She discussed the book and her participation in the Hubble telescope’s development and launch on BBC Radio 4’s Woman’s Hour and at the Royal Institution in London in March 2020.

In spring 2020, Sullivan traveled on an expedition aboard the Triton Submarines DSV Limiting Factor to the bottom of the Challenger Deep, the deepest known point in the ocean, becoming the first woman to reach the deepest known point in the ocean and the first person to travel to both Challenger Deep and to space.

In November 2020, Sullivan was named a volunteer member of the Joe Biden presidential transition Agency Review Team to support transition efforts related to the Department of Commerce.