He began learning the hammer technique at the age of 10, under the guidance of his father, Shigenobu Murofushi. By 15, he decided to take the sport seriously. His father, a renowned hammer thrower, played a significant role in his early training. He attended a high school in Narita known for its athletics programme.

| Season | Event | Rank |
|---|---|---|
| 2012 | Men's Hammer Throw | B Bronze |
| 2008 | Men's Hammer Throw | 5 |
| 2004 | Men's Hammer Throw | G Gold |
| 2000 | Men's Hammer Throw | 9 |
He is affiliated with the Mizuno Track Club in Japan. Over the years, he has received several awards and honours. In 2001, he was named Japanese Athlete of the Year. In 2006, he received the Smile of the Year Award from the Japan Dental Association.
Throughout his career, he faced several injuries. In 2005, a muscle injury to his left side prevented him from participating in the World Championships in Helsinki. He withdrew from the 2006 Asian Games due to a right calf injury and missed the 2008 Japan Grand Prix because of a back strain.
At the 2004 Olympic Games in Athens, Greece, he was initially awarded the silver medal. However, he was later awarded the gold medal after Hungary's Adrian Annus was stripped of his title for failing to attend compulsory drug tests.
Despite being relatively small for a hammer thrower, he developed an unorthodox technique to compensate for his size. By leaning back with each turn during his wind-up spins, he extended the radius between the axis of his spin and the head of the hammer. This technique allowed him to generate extra speed on the hammer.
His father, Shigenobu Murofushi, was known as the 'Iron Man of Asia' for winning five consecutive Asian Games hammer throw gold medals between 1970 and 1986. His mother was a javelin thrower from Romania, and his sister, Yuka Murofushi, has won gold medals in both hammer and discus events at Japan's national championships.
In 2007, he delayed his competition calendar by one month to work on his doctoral thesis. The thesis focused on biomechanics in hammer throwing. He received his PhD in June 2007 for his study titled 'Development of a System to Measure Radius of Curvature and Speed of Hammer Head during Turns in Hammer Throw'.
He believes that hammer throwing is not just about physical strength but also involves technique and understanding centrifugal force. He always drinks a cup of coffee before competitions as part of his pre-competition rituals.
Looking ahead, he plans to continue competing at international events while also contributing to academic research in sports science. His unique blend of athletic prowess and academic insight sets him apart in both fields.
He began learning the hammer technique at the age of 10, under the guidance of his father, Shigenobu Murofushi. By 15, he decided to take the sport seriously. His father, a renowned hammer thrower, played a significant role in his early training. He attended a high school in Narita known for its athletics programme.