In her fifth season as the head coach of the Cal Poly women's tennis program, Katharina Winterhalter had spent the previous seven seasons as an assistant, associate head coach and head coach at the city college and Division I levels.
In 2018, Winterhalter led the Mustangs to its first Big West Tournament win since 2016, reaching the semifinals for the first time since 2010. She also coached four players who earned Big West All-Conference honors, including Molly Reed who earned second-team honors after going 9-3 in singles play.
During her first season as head coach of the Mustangs, Winterhalter helped guide Cal Poly to four victories in 2015-16, of which included three wins at Mustang Courts. Winterhalter's Mustangs advanced to the quarterfinals of the Big West Conference Tournament, dispatching UC Riverside before falling to regular season champion, Long Beach State.
Under Winterhalter's watch, Cal Poly senior Dane Joubert and junior Zoe Oedekerk earned Big West All-Conference Second Team Doubles distinction, after four victories from the first position. Sophomore Molly Reed led the team with nine dual match victories, including five singles wins in a row to close the season.
Winterhalter arrived at Cal Poly from Fresno City College where she was the head assistant coach of both the men and women's tennis programs. Prior to her lone season with the Rams, Winterhalter served as the associate head coach of the Gaels women's program from 2011-14. Previously she spent three years as an assistant coach of the women's tennis team at Saint Mary's (2008-11).
While at Fresno City College, Winterhalter helped lead the men's program to a Big 8 South co-conference championship, achieving a 9-5 record, while also assisting the women's side to a semifinalist showing in the California Community College Athletic Association Championships.
Winterhalter helped lead Saint Mary's to a berth in the NCAA Division I National Championship for four consecutive years (2010-13), the Gaels' first West Coast Conference Tournament title in 2010, the West Coast Conference regular season championship in 2013 and a berth in the finals of the West Coast Conference Tournament in 2009, 2013 and 2014.
During her time at Saint Mary's, Winterhalter coached three West Coast Conference players of the year, three individual NCAA Championship participants, one NCAA singles All-American and earned Northwest Regional Assistant Coach of the Year honors in 2010. She helped coach Saint Mary's to a win over No. 7 Stanford in 2013 (at the time, only the third team to best Stanford at home since 1999).
From 2007-08, Winterhalter was a tennis professional at Fig Garden Swim and Racquet Club in Fresno and worked as a volunteer assistant coach at her alma mater, Fresno State, for two seasons from 2006-08.
As a volunteer at Fresno State, Winterhalter had many different roles that included player development, fundraising, camps and clinics, and other administrative duties. Winterhalter facilitated with developing players' technique, as well as tactical and mental aspects of the game.
For the last year, Winterhalter also has served as founder and head tennis professional at 2WTENNIS, which offers summer camps, private lessons, an after-school academy and a summer match circuit for tennis players of all ages.
As a player at Fresno State for four seasons (2002-06), Winterhalter compiled a 105-49 record in singles competition and 104-40 in doubles. She was an NCAA Division I Women's Tennis Championships Doubles runner-up in 2006 and a Women's All-American Tennis Championships Doubles runner-up during the 2005 season. Also in 2006, Winterhalter earned ITA Scholar-Athlete status and was named the Fresno State Athlete of the Year.
Winterhalter helped the Bulldogs to four straight Western Athletic Conference Championships and assisted Fresno State to the Round of 16 during the NCAA Division I Championships in both 2004 and 2006. Nationally ranked in both singles and doubles during her time at Fresno State, Winterhalter also earned All-American honors in doubles during the 2005-06 season.
In addition to her athletic excellence on the courts, Winterhalter achieved academic All-American status and was a four-time WAC student-athlete honoree that included an accumulative GPA of 3.40.
Winterhalter is a 2006 graduate of Fresno State with a bachelor's degree in civil engineering and earned her master's degree in kinesiology at Saint Mary's in 2012. She is pursuing another master's degree in leadership studies at Fresno Pacific.
Winterhalter is a United States Professional Tennis Association-certified elite tennis professional, Professional Tennis Registry-certified 10-and-under professional and has worked as a director, instructor and counselor at numerous summer tennis camps.