He was born on December 5, 1872 in Somerville, Massachussets, United States. His parents were Luther Batchelder and Mary A. (Leathe) Pillsbury, his father was a teacher in the high school. He was a descendant of William Pillsbury who was living in Dorchester, Massachussets, as early as 1641.
His interest in chess began when he was sixteen and for the next five years he was active in Boston chess circles.
After two years' attendance at high school and some slight training in commercial subjects, he abandoned his intention to prepare for business and devoted himself to chess.
In April 1893 he defeated in Boston the Berlin master, C. Walbrodt, 2-0, and later A. Schottländer of Breslau (now Wroclaw).
At Philadelphia, in 1893, he played four games blindfold, winning three and losing one. He was also an expert in checkers and bridge, and all three games, as well as memory feats, figured in his exhibitions. After reading once a list of fifty numbered words he could give the word corresponding to any number, the number of any word, or repeat the list backwards. In blindfold play he could repeat from memory the game at any board, or, indeed, begin at almost any point in each game a discussion of it.
One of his greatest exhibitions of blindfold play took place at the Franklin Chess Club, Philadelphia, on April 28, 1900, when he conducted twenty games simultaneously. At one time he played as "Ajeeb, the Automatic Player" in the Eden Musée, Boston, obtaining some regular income in this way. In master tournament play, his success in 1893 in finishing in the first half of a group including Emanuel Lasker (later world's champion), A. Albin, F. J. Lee, and J. W. Showalter, was his first notable achievement.
He won first place in 1895 in the Hastings Tournament in England, thus establishing himself among the great master-players of the world. At Vienna in 1898 he tied for first with Siegbert Tarrasch, but lost the play-off. He stood among the first three in twelve tournaments between 1894 and 1904, tying for first at Munich in 1900. In match play he defeated Showalter in 1897 and in 1898, thus acquiring the title of United States champion.
He was always a serious student, and contributed to the theory of chess in the defense against the Ruy Lopez, in the Petroff defense, and in introducing the modern aggressive Queen's pawn opening.
His death at thirty-three, in the Friends' Asylum, Frankford, Pennsylvania, was due primarily to a disease contracted in Russia, but resulted in part from the lack of resistance due to his irregular habits.
Harry Nelson Pillsbury was the youngest champion of the strongest tournaments of the time (the Hastings 1895 chess tournament). The dynamic style that Pillsbury exhibited during the tournament also helped to popularize the Queen's Gambit during the 1890s, including his famous win over Siegbert Tarrasch. He was the first American to engage professionally in extended chess exhibitions.
He was constantly distressed by the difficulty of earning a decent living by chess. The blindfold exhibitions from which he principally derived his income required many hours of concentrated mental effort, sometimes twelve at a stretch.
He had great ability to remember the sequence of moves, personal charm and versatility.
Pillsbury smoked strong cigars and sometimes took alcoholic stimulants; to his physical condition he gave little thought.
On January 17, 1901, Pillsbury married Mary Ellen Bush, daughter of Judge Albert J. Bush of Monticello, New York.
