Sadao Yoshioka Shihan was born in Hawaii on January 27, 1922 to Mr. and Mrs. Tasaburo Yoshioka who had emmigrated to Hawaii prior to Yoshioka Sensei's birth. He was the second-last born of seven children. As a youth, Yoshioka Sensei attended Japanese school and developed a deep interest in Japanese culture, an interest which stayed with him all his life. At 18 years he learned the carpenter trade and worked to help support his father and mother by working at the Pearl Harbor naval base. At age 23, he began working for the United States Postoffice, a career that lasted for 34 years. He was married and had three daughters and one son. During World War II, unlike some of the U.S. citizens of Japanese descent, Yoshioka Sensei was not extradited but continued his work as a postal employee.
Prior to training in Aikido, Yoshioka Sensei trained in Judo under Yukiso Yamamoto Sensei. When Yamamoto Sensei moved from Judo to Aikido, Yoshioka Sensei followed him and also began training in Aikido. This was at the Young Buddhist Association (YBA) of Honolulu, in 1955, only two years after the introduction of Aikido to Hawaii.
In 1959 Yamamoto Sensei left the YBA and opened the first branch of Hawaii Aiki Kwai at the old Nuuanu YMCA building. Yoshioka Sensei was appointed assistant instructor for the YMCA dojo.
In 1960 Yamamoto Sensei transferred to the newly built Waialae Avenue dojo assigning Yoshioka Sensei as head instructor at the Nuuanu YMCA.
When O-Sensei visited Hawaii in 1961, Yoshioka Shihan was his chauffeur and was able to spend much time with O-Sensei.
In 1963 Yoshioka Sensei began practicing misogi at the Manoa Waterfalls. This monthly training was to continue for many years.
In 1967 on the recommendation of Koichi Tohei Sensei, Yoshioka Sensei was sponsored by the Honolulu Aiki Dojo under Dr. Yorio Wakatake and Hawaii Aiki Kwai to visit Japan on February 28, 1967 to train for six weeks under O-Sensei. While in Japan Yoshioka Sensei was invited by O-Sensei to his home in the country at Iwama. Yoshioka Sensei was invited to have tea and sake with the Founder, and O-Sensei also put on a demonstration at the Aiki Shrine for Yoshioka Sensei. While in Japan, Yoshioka Sensei lived with Akira Tohei. It was through Mr. Tohei's support, tutelage, and encouragement that he was able to learn the intricacies of Japanese etiquette and philosophy. Yoshioka Sensei was also the Hawaii delegate at the groundbreaking ceremonies for the new Hombu Dojo building. At this time Yoshioka Sensei was 5 dan.
During his stay in Japan, Yoshioka Sensei was sponsored by Akira Tohei to complete the very rigorous Misogi training at the Ichiku-kai Dojo. Yoshioka Sensei was both the oldest member of the class and the first foreigner to graduate from this school. Later Yoshioka Sensei was to sponsor two of his own students to take the Misogi training in Japan, Mitsuko Smith, and Randy Scoville (who is currently the Chief Instructor of the Hawaii Aikido Federation).
In 1970, upon the retirement of Yukiso Yamamoto from the Hawaii Aiki Kwai, Mr. Yoshioka was appointed by the Hawaii Aiki Kwai as its next Chief Instructor. This appointment was approved by the Aikido World Headquarters in Tokyo.
In June 1975 Yoshioka Sensei organized his first tour of students to Japan to study Japanese culture. Over the next fifteen years Yoshioka Sensei was to conduct four such tours. On the first tour, Yoshioka Sensei was accompanied by forty students. During the two week tour they visited Kyushu and the Kansei area. They also visited the Aikido shrine in Iwama, Ibaragi Prefecture. Closing their visit of Japan, they practiced for two days at Hombo dojo.
In 1976 Dr. Yorio Wakatake was elected president of the United States Aikido Federation, recently formed in New York City. Yoshioka Sensei was also elected a member of the Federation Council.
In 1977 Moriteru Ueshiba Sensei visited Hawaii for the first time. In December of 1977, Yoshioka Sensei and Dr. Yorio Wakatake traveled to Chicago for the 3-day United States Aikido Federation Convention and Seminar where Yoshioka Sensei was one of four Shihan comprising the Technical Committee and providing instruction for the seminar.
March 1978, Yoshioka Sensei received a resolution from the City and County of Honolulu in recognition of his contribution of fifteen years of volunteer instruction of Honolulu Police Department recruits in Aikido techniques. The resolution notes that his instruction "has enhanced the capability of police officers in protecting the public." Yoshioka Sensei lead a second tour of Japan during this year.
In August 9-13, 1978, Hawaii Aiki Kwai, under the leadership of Yoshioka Sensei, hosted the Second International Aikido Federation Congress at Hawaii Aiki Kwai Headquarters.
In early 1979 Yoshioka Sensei left the Hawaii Aiki Kai association and returned to teaching at Nuuanu YMCA. Here he spent his remaining years teaching not only Aikido, but many of the arts and activities which are part of Japanese culture such as Kadomatsu, wood carving, misogi and mochi pounding,
For several years starting in 1979, Yoshioka Sensei conducted yearly seminars at Camp Paumalu in the mountains above Waimea on the north shore of Oahu.
In 1980 Yoshioka Sensei organized the first of what became a yearly mochi pounding in preparation for Kagami Biraki. The first pounding was held at the home of Jack LaRue Sensei. The Hawaii Aikido Federation continues this New Year's tradition.
In 1982 Yoshioka Sensei opened a branch dojo at St. Louis School in Kaimuki. Dr. Robert Little Sensei was assigned as head instructor of the dojo. The St. Louis dojo now meets at the UH Manoa.
In 1982 Yoshioka Shihan was diagnosed with lymph cancer. Although he refused surgery fearing its impact on his Aikido, he consented to a therapeutic course of chemotherapy. During the therapy period, Sensei continued to teach classes as usual.
In 1984 the YBA of Honolulu asked Yoshioka Sensei to open a new Aikido dojo at their facilities. Yoshioka Sensei appointed Sogi Sensei as the head instructor for the YBA Dojo.
In June of 1985 Yoshioka Sensei conducted a third tour to Japan, and was invited with his students to the home of Kisshomaru Ueshiba Doshu.
In 1986 Washington, D.C. Aikikai chief instructor, Dr. Clyde Takeguchi, invited Yoshioka Sensei to conduct a seminar in Washington, DC. Hawaii Senator Spark M. Matsunaga presented Yoshioka Sensei with a United States flag which had flown over the nation's capitol.
In 1987 Yoshioka Shihan formed the Hawaii Aikido Federation in order to provide his students with direct access to Japan and the ability to promote students directly from Hawaii. The Hawaii Aikido Federation was incorporated under the State of Hawaii as a non-profit corporation. Yoshioka Sensei was established as the Chief Instructor and a board of directors was selected.
In August 1988 Yoshioka Sensei conducted a fourth and last tour of Japan. This tour was on the occasion of the Fifth International Aikido Federation Congress and General Assembly at Tanabe. The city of Tanabe, Wakayama Prefecture (where the Founder was born), erected a statue of Morihei Ueshiba in Ogigahama Park. The Hawaii tour members attended the unveiling of this statue. Yoshioka Sensei was among a very few people who were honored to receive bronze replicas of the statue. This presentation was a token of Hombu Dojo's recognition of Yoshioka Sensei's efforts to spread Aikido and its philosophy in Hawaii.
In 1989 Yoshioka Shihan opened the HAF Kokokahi Aikido Dojo at the Kokokahi YWCA in Kaneohe. Randy Scoville Sensei was appointed as the head instructor of the club. With the opening of this dojo there were four dojo's belonging to the Hawaii Aikido Federation: Nuuanu Aikido Club, HAF Aikido Club of UH Manoa, YBA Aikido Club, and the Kokokahi Aikido Club.
In late 1989 Yoshioka Sensei was diagnosed with a recurrence of the cancer which he had been treated for in 1982 which had been thought to be in remission. He began another treatment of chemotherapy but passed away due to iatrogenic complications in January 19, 1990.