Sagen began shooting with her local 4-H club, which taught her organization and her grandpa, who taught her patience. Having got her start as a high-power shooter, Maddalena quietly emerged on the scene as one of the top contenders in Air Rifle. She earned a spot on the California Grizzly junior service rifle team where she helped them win the Whistler Boy Trophy in 2011 and Freedom’s Fire Trophy in 2013. Her coach Robert Taylor suggested NCAA shooting, so she went on to learn to compete in both air and smallbore rifle.
She walked-on to one of the best rifle programs in the country at University of Alaska Fairbanks, and red-shirted her first season in 2013. To gain more match experience her coach, Dan Jordan, suggested
she compete at the World Cup tryouts in May 2014, which ultimately proved successful as she earned the privilege to compete internationally. She made the World Championship team again in 2018. During her NCAA career at UAF she was an eight time All-American from 2014-2018.
Sagen enlisted on active duty in March 2019 and was assigned to the U.S. Army Marksmanship Unit (USAMU) in Ft. Benning as a shooter/instructor.
She made her Olympic debut at the 2020 Tokyo Summer Games where she placed 5th overall in Women’s 50m Rifle 3 Positions
Her international success continued in 2021 where she earned three ISSF World Cup Medals. In 2022 she secured two medals at the ISSF World Championships and two gold medals at the 2022 Championship of the Americas Games.
- 2023 Pan American Games Champion Women's Air Rifle; Silver, Women's 50m Smallbore Rifle; Bronze, Mixed Team Air Rifle
- 2023 ISSF World Championship: Gold and new World Record, Women’s 50m Rifle 3 Positions Team; Bronze, Women’s 50m Rifle 3 Positions
- 2022 ISSF President's Cup: Bronze, Women's 10m Air Rifle
- 2022 CAT Games: Gold, Women’s 10m Air Rifle
- 2022 CAT Games: Gold, 10m Air Rifle Mixed Team
- 2022 CAT Games: Gold, 10m Air Rifle Women’s Team
- 2022 CAT Games: Gold, 50m Prone Rifle Mixed Team
- 2022 CAT Games: Gold, 50m Rifle 3 Position Women’s Team
- 2022 CAT Games: Gold, 50m Prone Rifle
- 2022 ISSF World Championships: Gold, Mixed Team 50m Prone Rifle; Bronze, Women's Air Rifle Team
- 2022 USA Shooting Rifle National Championships: Gold, Women's Air Rifle; Gold, Women's 50m Smalbore
- 2021 ISSF New Delhi World Cup: Silver Medalist (Women’s 10m Air Rifle Team)
- 2020 Tokyo Olympics, 5th place 50m 3-position Rifle
- 2020 NRA Blackhawk Championships, Gold Medalist (Prone) (New National Record)
- 2020 ASSA National Championships, Gold Medalist (Smallbore) (New National Record)
- 2014 World Team Member