Parry's family was distinguished. His father, Thomas Gambier Parry, was a director of the East India Company; Thomas' great-uncle was Lord Gambier, Admiral of the Fleet. Salt water was, as it were, in Parry's blood, and one of his lifelong favorite recreations was piloting his own seaworthy yacht.
Parry must have seemed unusually talented for a young man of his day. One summer while at Eton, Parry had to travel to Stuttgart in order to study composition with the English pedagogue Henry Hugo Pierson, who had left England for an artistic climate more congenial to his endeavors. While still at Eton, Parry earned the Oxford bachelor of music degree, subsequently entering Exeter College at Oxford. His marriage to Maude Herbert, sister of his school chum George Herbert, 13th Earl of Pembroke, forced him to seek nonmusical work with Lloyd's register in London while establishing himself as a composer, but it was while working in London that he met and allied himself with teacher and pianist Edward Dannreuther, who was a great influence on the young man, arranging for private performances of much of Parry's early chamber music, and introducing him to the music of Wagner by procuring for Parry tickets for the second ever performance at Bayreuth of the Ring. Dannreuther was the pianist at Parry's first public triumph, a performance of his Piano Concerto in F sharp major at the Crystal Palace in 1880.
Parry made his mark at the many choral society festivals throughout England, with 1880's Scenes from Shelley's Prometheus Bound, Blest Pair of Sirens (1887; to words of Milton), a setting of Milton's L'allegro ed il penseroso (1890), the oratorio Job (1892; considered by some to be his masterpiece of the 1890s), and the sublime Invocation to Music, with words by Robert Bridges (1895). In these works, Parry came up with a tangible English style, all the more noteworthy for its originality and wit.
Parry got in on the ground floor when it came to creating a viable musical education establishment for England, joining the staff of the Royal College of Music upon its opening in 1883. Eleven years later he succeeded Sir George Grove as the RCM's director. Parry also was Choragus at Oxford, beginning in 1883, and in 1900 took John Stainer's place as professor of music there. Parry wrote extensively and quite vigorously about music, in 1893's The Art of Music, Style in Musical Art (1911), and the unpublished Instinct and Character. He also wrote an excellent critical biography of J.S. Bach (1909), and was responsible for the third volume of the Oxford History of Music, Music of the Seventeenth Century.
Toward the end of his life, Parry was honored with knighthood and a baronetcy, as well as the genuine affection of the many composers who had benefited from his prescient and understanding way with helping his students find their own voices. In 1908, a breakdown of health forced Parry to retire from his administrative posts, but instead of causing a cessation creative activity, this crisis actually brought about what is frequently described as his "Indian summer," in which some of his very finest music was written.