Noguchi began during her school time with the running training, in the first year of secondary school. First, they ran 3000 meter race and marathon relay teams ( Ekiden ). In 1997, she was inducted into the company team of apparel maker Wacoal. In 1999, she joined the crew of the commodity futures trader globaly. In Japan it is common that large companies have their own teams for long-distance runners, along with the entire coaching staff (ie, similar to cycling in Europe). The athletes are then legally as employees.
After Noguchi had won the half marathon of Inuyama 1999, she decided to specialize in this discipline. In that year, Noguchi was classified as second in the world rankings. She was second in the World Half Marathon Championships and in the following two years Fourth 1999. In 2001 she won the Japanese firms Championship. By 2004, she took part in 24/2 marathons, of which they won 14, so she was referred to as " queen of the half marathon ." It was only twice beaten by a Japanese woman. In March 2002, she performed at the Nagoya Marathon for the first time the full distance and won the race at first in 2:25:35. A year later she improved as the winner of the Osaka Women's Marathon this brand at 2:21:18.
In a marathon, the World Athletics Championships 2003 in Paris / Saint- Denis she finished second behind Catherine Ndereba (KEN ). At the Olympic Games in Athens, she won the challenging marathon in a time of 2:26:20 before Catherine Ndereba and Deena Kastor (USA). In 2005, she ran the Berlin Marathon, where even their countrywomen Naoko Takahashi and Yōko Shibui had remained under 2:20 with 2:19:12, both -distance as well as a new Asian record.
In November 2007, she made an impressive marathon times back when she set a course record with 2:21:37 at the Tokyo International Women's Marathon.
Mizuki Noguchi has a competition weight of 41 kg at a height of 1.50 m.