Ito started skating at age four at a rink in Nagoya and approached Machiko Yamada, who would become her coach throughout her career, on the same day. She landed her first triple jump at age 8. She went to live with her coach after her parents' divorce when she was 10.
Ito made her first appearance at a major international competition at the 1981 World Junior Championships. She placed 20th in the compulsory figures but won the free skating with a triple loop, a triple salchow, and two triple toe loop combinations. She finished 8th in the overall standings. At this event, the 11-year-old Ito was only 3'11" tall and weighed 53 pounds. She was nicknamed the "Jumping Flea" due to her diminutive size and powerful jumps.
At the 1982 World Junior Championships, Ito won both the short program and free skating, but again weak compulsory figures kept her off the podium, in 6th place overall. Her free skating at this event included a triple flip and a triple toe loop-triple toe loop combination, and she landed a triple lutz in the exhibition.
Ito did not compete at the 1983 World Junior event, which took place in December 1982, after having sustained a broken ankle earlier that year. In the fall of 1983, she made her senior international debut at the Ennia Challenge Cup in the Netherlands, a competition that featured the short program and free skating only, without compulsory figures. She finished second to Katarina Witt, who went on to win the Olympic title a few months later. Ito's free skating included six triple jumps—flip, lutz, loop, salchow, and two toe loops—and she also completed a double loop-triple loop combination in the short program. At the 1984 World Junior Championships, she won both the short program and free skating but finished third overall due to a low placement in the compulsory figures. Ito also competed at the 1984 World Championships, where she finished 7th.
Ito won her first national championship in the 1985 season, but was unable to compete at that year's World Championships after again breaking her ankle.
Ito placed 5th at the 1988 Winter Olympics in Calgary, Canada. In Calgary, she performed a double loop-triple loop in the short program, and seven triples in the free skating: Lutz, flip, double axel-half loop-triple salchow, loop, triple toe loop-triple toe loop, and salchow. She received 7 "5.9" marks for technical merit, despite skating before the final flight. She became the first woman to land seven triples in a free skating. Later that same year, she perfected the triple Axel, which she had been working on since her early teens, and landed it at a regional competition in the Aichi prefecture. She became the first woman to land it in international competition at the 1988 NHK Trophy. She then repeated the feat at the World Championships in 1989. Her win at the 1989 World Championships was the first world title in the sport for an Asian competitor. She received five 6.0s for technical merit.
During the start of the 1989–90 season, Ito made history again at the 1989 NHK Trophy competition, where she received a rare 6.0 technical/6.0 artistic score from the Hungarian judge, and again landed seven triples, including the triple axel. At the 1990 World Championships, Ito was 10th after the compulsory figures but placed first in both the short program and the free skating and won the silver medal, second to Jill Trenary. Compulsory figures were eliminated from competitions following that season. Ito commented: "In training, I spend about two-thirds of my time on the figures. So I will sort of miss them as part of my life. But I will not miss them in the actual event." In June 1990, she was invited to meet Emperor Akihito.
Ito had chronically sore knees due to her jumps. In February 1991, she underwent surgery to remove two glandular cysts in her throat and was in the hospital for 18 days. In March, at the 1991 World Championships, Ito collided with France's Laetitia Hubert during a practice session – her hip and the top of her foot were bruised. In the short program, she placed her jump combination too close to the corner of the rink and fell into the opening in the boards for the television camera but was back on the ice within seconds. She finished 4th at the event.
At the 1991 Grand Prix International de Paris – a pre-Olympic event in Albertville – Ito beat Kristi Yamaguchi by completing a triple axel and five other triple jumps in her free skating. During the warm-up before the free skating, she landed a triple Axel-triple toe loop jump combination, which has still not been equaled by any other female skater.
At the 1992 Winter Olympics, Ito placed fourth in the short program. During a practice session, Surya Bonaly of France performed a back flip near her. Ito's free skate began with a failed triple Axel but she attempted it again at the end of her program and landed it successfully, becoming the first woman to land one in the Olympics. She won the silver medal, and apologized to her country for not winning the gold. Ito turned professional afterwards, bringing the triple Axel for the first time to the professional ranks, and performed with ice shows in Japan. She briefly returned to competitive skating in the 1995–96 season, but without her former success.
During the peak of her career, Ito performed much the same jump content as the top male skaters of the time. She was the first ladies' skater to perform a triple-triple jump combination and the first to perform the triple axel. In March 1990, Jill Trenary said, "I was in awe of how high she jumps." In 1990, Scott Hamilton said "it will be 50 years before we see anything like Midori Ito again," and Toller Cranston, the same year, noted that "she is beyond 6.0."
Ito lit the Olympic flame during the opening ceremonies of the 1998 Winter Olympics.
Ito returned to competitive figure skating in 2011. She competed at the ISU Adult Figure Skating Competition and placed second in her category, Ladies' Masters Elite II. Ito repeated her second-place finish the following year. In 2013, on her third year competing at the ISU Adult Figure Skating Championship, she took the title with a 12 points margin over the second place.World Champion (1989).
First woman to land a triple-triple jump combination (1981).
First woman to land a double loop-triple loop combination (in the short program) (1983).
First woman to land five different triple jumps in competition (1983).
First woman to land a triple Axel in competition (1988).
First woman to land six different triple jumps in competition (1989).
First woman to land a triple Axel in the Olympics (1992).
Inducted into the World Figure Skating Hall of Fame (2003).
Ito landed 18 triple axels in competition.伊藤みどりのフィギュアスケート・ライフ努力編 (2006) – ASIN B000O77KHK
伊藤みどりのフィギュアスケート・ライフ人生編 (2007) – ASIN B000OI1BXS
伊藤みどりのフィギュアスケート・ライフ (2007) – ASIN B000SB2ZT0
タイム・パッセージ―時間旅行（1993）- ISBN 978-4-314-10081-6
伊藤みどり物語 (1992) – ISBN 978-4-87208-036-0
氷上の宝石―伊藤みどり写真集 (1993) – ISBN 978-4-317-80036-2