Jiro Sato attended to Waseda University and studied economics. He abandoned his studies in 1933 to pursue tennis.
He debuted on the international tennis scene in 1929 when the touring Racing Club de Paris visited Japan for a series of exhibition matches. He notably defeated tennis legends Jacques Brugnon, Raymond Rodel and Pierre Henri Landry, only losing to Henri Cochet.
In 1930 he was the runner-up for the Japanese championships, which he finally did win the next year. Also in 1930 he was a runner-up for the Mid-Pacific Invitational tournament losing to American Cranston Holman and the doubles final as well.
In 1931 he lost the Miramar L.T.C. title in Juan-les-Pins against his brother Hyotare Sato, won the doubles, and was a finalist in mixed doubles. He clinched the West-England Championship in singles and doubles. He was defeated by Jean Borotra for the British Covered Court Championships title. He partnered his brother to gain the Beau Site Club de Cannes second meeting trophy and the St. Raphaël T.C. title. In singles competition he claimed the Country Club de Monte-Carlo second meeting title (the same tournament in which the Sato brothers reached the doubles final). He became Dutch doubles champion alongside Minoru Kawachi. In July he beat Vernon Kirby for the Tunbridge Wells Championship. He captured the Midland Counties Championships in singles and mixed doubles the same month and only losing the doubles final.
Between July and November 1931 he won 13 singles titles in Great Britain. He met Fred Perry twice for the Pacific Southwest Championships title in 1932 and 1933, losing both times. In August 1933 he partnered compatriot Ryosuke Nunoi to win the doubles title at the German Championships in Hamburg.
From 1931 to 1933 Sato played in ten ties for the Japanese Davis Cup team and won 22 rubbers and lost only six, compiling a 79% winning record.
On April 4, 1934, Jiro Sato was on the ship N.Y.K. Hakone Maru crossing the Strait of Malacca to Europe for a Davis Cup match against the Australia Davis Cup team in the second round of the 1934 International Lawn Tennis Challenge. Earlier in the day he complained of stomach pains and thus had no appetite and kept to his cabin. He considered leaving the ship at Singapore, which he did for a medical examination. The exam revealed no reasons for his health problems and it was concluded that his problems were psychological. Sato was nervous and feared that his illness would be an obstacle for his team to win. As the day passed, the Japan Davis Cup team was given a banquet hosted by the Japanese consul to Singapore. Sato was present and was further pushed by the consul and his teammates to proceed with the trip and sail to Europe. That same day a cable was received from the Japanese Lawn Tennis Association insisting on Sato's participation in the Davis Cup and that the voyage should be resumed without delay.
At 11:30 p.m. on April 5, 1934, before reaching Penang, Sato was found missing by his compatriot Jiro Yamagishi. The last time he was seen was at 8:30 p.m. when he had dinner in his cabin.
However, it got more and more difficult for him to endure the enormous pressure from Japan. It is believed that pressure drove him to throw himself overboard into the Strait of Malacca on April 5, 1934, at 26 years of age.
Quotes from others about the person
Fred Perry said: "Sato was one of the cheeriest men he had ever known".
Bunny Austin added: "He had a great sense of humor...He always gave the impression that he would be the last man on earth to come to such an end".
Ryuki Miki stated: "Sato was a joyful person who loved jokes and making people laugh."
His fiancée recalled that Sato hoped he could stay at Singapore. She further added: "I believe Jiro committed suicide solely from a sense of responsibility after he had acceded to the tennis association's urgings to proceed to Europe, even when he wanted to return from Singapore. To the end of my life I shall regret that it was the order of the Japanese Lawn Tennis Association that resulted in his death. Jiro was a man of honor and he played every time for the honor of Japan."
He was engaged to Sanae Okada in 1934, one of Japan's best female tennis players.