At the 2008 FINA Youth World Swimming Championships, Knutson won a total of five medals, all of them gold. At the 2008 Short Course Nationals, Knutson broke Katie Hoff's American record in the 400-yard individual medley with a time of 4:00.62, a record which has since been broken by Julia Smit. At the 2009 Junior Pac Pacs, she set five meet records while winning seven gold medals and a bronze.
At the 2009 National Championships, Knutson qualified to swim in the 4x200 m freestyle relay at the 2009 World Aquatics Championships in Rome by placing fifth in the 200 m freestyle. In Rome, Knutson swam in the heats of the 4x200 m freestyle relay (with Ariana Kukors, Alyssa Anderson, and Lacey Nymeyer) and won a silver medal after the United States placed second in the finals. As the second leg, Knutson had a 1:57.73 split.
At the 2010 National Championships, Knutson did not qualify to swim in any individual events at the 2010 Pan Pacific Swimming Championships. Knutson placed 4th in the 400 m freestyle, 5th in the 200 m freestyle, 6th in the 400 m individual medley, and 19th in the 200 m butterfly.
At the 2011 World Aquatics Championships in Shanghai, Knutson won a gold medal in the 4×200-meter freestyle relay with Missy Franklin, Katie Hoff, and Allison Schmitt, with the team finishing ahead of Australia and China. As the second leg, Knutson had a 1:57.18 split.
Knutson started swimming at the age of 9. Her parents, Jim and Ronda, were both college athletes. Her parents have chosen for her a Norwegian name (although they both have American citizenship, their parents are Norwegians).
Knutson's hometown is Minot, North Dakota, but she has trained at the University of Florida after briefly training with Auburn University then FAST in Fullerton, California. Because of geographic proximity, Knutson used to swim in so many meets in Canada that she was once mistakenly named one of that country's top 12-year-old swimmers.
Last updated August 13, 2010. All times were set in a 50 metres pool.