Robert "Bobby" Costello started as the U.S. Eventing Team Chef d'Equipe and Technical Advisor for the program in 2022. With a decorated career as an international athlete, actively competing up until 2010, Costello was a member of the World Championship Team and placed in the top 10 as an individual at the Sydney Olympic Games in 2000. As the U.S. Technical Advisor, Costello led the U.S. Eventing Team to several key championship results, including a team silver at the 2022 FEI World Eventing Championships in Pratoni del Vivaro Italy and a team silver at the 2023 Pan American Games in Santiago, Chile.  

In 2018, Coon expanded her training by working with Richard Waygood and Olivia Oakley, supported by the Karen Stives Endowment Fund Grant from the United States Equestrian Team (USET). In 2019, she was named to the USEF Developing Potential Training List, marking her first inclusion on a high-performance roster.  
 
In 2024, Coon competed as a member of the Defender U.S. Eventing Team at the FEI Eventing Nations Cup in the Netherlands, where the team finished in second place. Coon and her horse, Cute Girl, achieved notable success, securing third place individually—marking one of the highest placements for a U.S. combination in nearly a decade. 

Coon participated in various competitions throughout 2024, including events in Le Lion d'Angers, Boekelo, and Aachen, where she consistently demonstrated strong performances on multiple horses. 

Most recently, Coon finished top five at Luhmuhlen CCI5*-L with Kapriccio, her highest finish at the CCI5*-L. 

Mary Bess Davis found herself on the back of a horse from a young age, eventually finding a passion for the sport of eventing. Davis attended the University of Georgia while managing barns and producing horses through the ranks of the FEI levels. She began her FEI career in 2002 with her own Mojo Rising, whom she rode through the CCI4* level. In 2008, Davis was named to the USEF Developing Rider List, having numerous top ten finishes in the years following with her string of horses that she had developed through the levels. After breaking her back, which left her sidelined from international competition for numerous years, Davis made a comeback in 2019. Over the past few years, she has continued to develop her string of horses. In 2021, she took her own Imperio Magic to his first FEI competition and has since ridden him at numerous CCI4*-L competitions. During their 2022 season, the pair had six top ten placings, including a second-place finish at The Event at Terranova CCI4*-S.

Davis and Imperio Magic had five CCI4* starts in 2024, including being a part of the U.S. Eventing Team at the FEI Nations Cup Netherlands CCIO4*-NC-L. 

Phillip Dutton began riding horses on his family farm while growing up in Australia. He moved to the U.S. in 1991 to prepare for the Atlanta 1996 Olympic Games and continued representing his native country until 2006, when he became a U.S. citizen. Dutton has been a mainstay on U.S. teams ever since. Dutton has competed in nearly every Olympic Games in eventing since 1996, winning team gold with Australia in Atlanta 1996 and Sydney 2000, and represented the U.S. Eventing Team in 2008, 2012, 2016, and 2020. He won individual bronze with Mighty Nice at the 2016 Olympics in Rio de Janeiro. He has competed in seven FEI World Equestrian Games, representing the U.S. for the first time in 2006. He won team gold and individual silver at the 2007 Pan American Games with Truluck and team gold at the 2015 Pan American Games with Fernhill Fugitive.  

Dutton has been the top-finishing American at the Kentucky Three-Day Event several times, winning the USET Foundation Pinnacle Cup in 2017 with Mr. Medicott, 2015 with Fernhill Cubalawn, 2010 with Woodburn, and 2007 and 2008 with Connaught. In 2008, he was also the overall winner of the event. Dutton and Z were fourth at the 2022 Maryland 5 Star and fifth at the 2023 Land Rover Kentucky Three-Day Event presented by MARS Equestrian™ CCI5*-L. 

Dutton has continued to campaign with a top string of CCI4* and CCI5* mounts. Strong top five finishes for both Possante and Denim in the 2025 Lexington CCI4*-S in April helped build momentum for Dutton moving into the summer season. A highlight moment of the summer was a podium with the Defender U.S. Eventing Team at 2025 CHIO Aachen, where Dutton and Possante helped the team secure their third consecutive silver medal in the CCIO4*-NC-S competition, and where they finished in 11th individually, just ahead of barn mate Denim, who took 14th overall. Dutton continued to carry that form through the remainder of the 2025 season, finishing as the overall runner-up in the US Equestrian Open Eventing Series standings, and capped the year with a sixth-place finish aboard Denim at the inaugural US Equestrian Open Eventing Final CCI4*-L at Morven Park International Equestrian Center in October 2025.  

In 2026, Dutton continues to produce results with a talented string of horses, which has included numerous top ten finishes in international competition, including a top ten finish at the Defender Kentucky Three-Day Event with Possante, where they took eighth overall. Dutton and Denim captured the win in the CCI4*-S at Bromont in June, where they finished on their dressage score of 29.3.  

Dutton resides in Pennsylvania with his wife Evie, twin daughters, Mary and Olivia, and stepdaughter Lee Lee. 

With 47 FEI career starts at the age of 21, Cassie Sanger is one of the country’s top young eventers. Sanger started riding at the age of eight after being encouraged by her grandmother. She leased her first horse, Danger Mouse, from Caroline Pamukcu in 2021 before adding Redfield Fyre and Fernhill Zoro to her impressive string of horses.  

Sanger’s international success took off in 2023 when she and her own Fernhill Zoro placed top 5 in the TerraNova CCI4*-S in Myakka City, Fla. That same year, she was selected to the 2023 Eventing 25 Emerging Athlete Program and later selected for the U.S. Eventing European Development Tour where she made her Nations Cup debut at the FEI Eventing Nations Cup Poland CCIO4*-NC-S, helping the U.S. Eventing Team secure a silver medal finish. Sanger later added another podium finish at Bromont in the CCIU253*-S with Redfield Fyre and delivered the team’s top dressage score at the FEI Eventing Nations Cup Netherland CCIO4*-NC-L with Fernhill Zoro.

In 2024, Sanger continued to make her mark, earning a spot on the Eventing Development 25 Program List. She and Fernhill Zoro were a part of the winning team at the USEF Futures Team Challenge at Carolina International and secured top 5 finishes with both Redfield Fyre and Fernhill Zoro at the Defender Bramham International CCIU254*-L. She and Fernhill Zoro were selected for the 2024 U.S. Eventing European Development Tour and the FEI Eventing Nations Cup Great Britain CCIO4*-NC-S. She returned to Bromont for another top finish, this time with Fernhill Zoro, and competed as the youngest athlete in the field on the U.S. Eventing Team at the FEI Nations Cup Netherlands CCIO4*-NC-L with Redfield Fyre.  

Entering 2025, Sanger was named to the Eventing Development 25 Program and kicked off the season with a win aboard MT Luxaan at the Carolina International CCI2*-S.