Katherine Reagan Campbell was born on September 3, 1998 in Lewisville, Texas to Michelle and Michael Campbell. She has a younger brother, Davis who is a baseball player and a shih tzu named PJ. Currently, Reagan is a senior at Elite Learning Academy at Texas Dreams Gymnastics. It is a homeschooled program that allows Reagan to have more flexible schedule with training and schoolwork. During Reagan's spare time, she enjoys drawing, cooking and running.

Reagan's mom was a cheerleader and she enrolled her into gymnastics as a toddler so she could learn to tumble. Her mom never thought she would become a gymnast! Reagan started her gymnastics career at Shoal's Gymnastics in Alabama at the age of two. When her family moved back to Texas, Reagan started training at Texas Dreams Gymnastics and has been there ever since.

Reagan made the TOPs National Diamond Team in 2006 and TOPs National Team in 2007. As a level 8 gymnast in 2008, she placed first on uneven bars and third on floor exercise at the Rose City Classic. She grabbed gold medals on uneven bars, floor exercise and in the all-around at the Parkettes Invitational. She qualified to the Level 8 Regionals, finishing seventh all-around and second on uneven bars. Reagan made the TOPs National Team again in the fall.

As a level 9 gymnast in 2009, Reagan placed fifth in the all-around and first on balance beam at the Texas Prime Meet. At the National Gymnastics Challenge in Athens, GA, she grabbed gold medals on balance beam, floor exercise and in the all-around. She qualified to the Level 9 Regionals after finishing sixth on balance beam with a 9.700 and 17th overall. In the early summer, she qualified to HOPES. She won the all-around title at both Parkettes Elite Qualifier and Texas Elite Qualifier. At the US Challenge in Des Moines, IA, she placed fifth in the all-around, third on balance beam and fourth on floor exercise.

In 2010, Reagan won the uneven bars title as a level 10 gymnast at the Texas Prime Meet. She qualified to HOPES again in February after finishing second in the all-around and first on vault and floor exercise at the Buckeye Elite Qualifier. At the Arizona Elite Qualifier, she placed first on balance beam and floor exercise. She concluded her 2010 season at the US Challenge in Chicago, IL where she finished first on uneven bars, floor exercise and in the all-around in her age group.

Reagan missed most of 2011 season due to an injury. She won the balance beam title with a 14.650 at the Florida Elite Qualifier in June. In 2012, Reagan came back as a level 10 gymnast and competed on two events all season. She finished first on uneven bars and balance beam at the Rose City Classic. At the State Championships, she placed sixth on uneven bars and balance beam. Reagan finished her 2012 season at the Region 3 Championships with a silver medal on vault.

Reagan had a great 2013 season. She placed fourth in the all-around and second on uneven bars and balance beam at the Atlanta Crown Invitational. At the Texas Prime Meet, she grabbed gold medals on vault, balance beam, floor exericse and in the all-around with a 38.125. This qualified Reagan to the Nastia Liukin Supergirl Cup in March. A few weeks later, she won the all-around again at the Heart of a Champion Invitational in California. She also placed first on vault, balance beam and floor exercise. At the WOGA Classic, Reagan placed first on vault and in the all-around with a 38.750. On March 1st, Reagan traveled to Worcester, MA for the Nastia Liukin Supergirl Cup. She finished impressive fifth in the all-around with a 37.925 out of 34 gymnasts, including some of top level 10's from across the nation. Reagan had a great meet at the State Championships, finishing first on uneven bars and balance beam as well as second in the all-around with a 38.625. At the Region 3 Championships, she placed fourth on vault and seventh in the all-around. This qualified Reagan to the Junior Olympic Nationals where she finished third in the all-around, second on balance beam and third on uneven bars and floor exercise. She made the Junior Olympic National Team.

In 2014, Reagan started her season at the Texas Prime Meet, finishing first on uneven bars, balance beam and in the all-around with a 38.700. This qualified Reagan to the Nastia Liukin Supergirl Cup for the second time. She grabbed gold medals on uneven bars, balance beam, floor exercise and in the all-around at the Classic Rock Invitational and WOGA Classic. In March, Reagan traveled to Greensboro, NC for the Nastia Liukin Supergirl Cup where she placed eighth in the all-around and fifth on floor exercise. At the Region 3 Championships, Reagan finished second in the all-around, first on balance beam and second on floor exercise. She qualified to the Junior Olympic Nationals in Jackson, MS, finishing fourth in the all-around with a 38.225 and second on balance beam. Reagan made the Junior Olympic National Team.

Reagan started her 2015 season at the AOGC Invitational, finishing first on uneven bars and balance beam. At the Rose City Classic, she placed fourth in the all-around and second on vault and balance beam. She had a great meet at the State Championships where she finished first in the all-around with a 38.200, first on floor exercise and second on vault and uneven bars. Reagan placed third in the all-around with a 38.350, second on balance beam and third on uneven bars at the Region 3 Championships. She qualified to the Junior Olympic Nationals in Des Moines, IA where she placed sixth in the all-around with a 38.000, second on balance beam and eighth on uneven bars.

In 2016, Reagan finished fourth on vault at the State Championships, her only event. At the Region 3 Championships, she placed first in the all-around with a 37.875 and first on uneven bars and balance beam. She qualified to the Junior Olympic Nationals in Ft. Worth, TX where she placed fifth in the all-around with a 38.250 and fourth on balance beam and floor exercise.

Reagan trains about 30 hours per week at Texas Dreams Gymnastics in Coppell, Texas under coaches Kim Zmeskal-Burdette and Chris Burdette. Reagan verbally committed to LSU for the 2017-2018 school year.