Jerry Brainard, an organist and harpsichordist who was the artistic director of the early-music ensemble Badinage, died last Saturday. He was 35 years old.

Mr. Brainard, who was born in Paynesville, Ohio, won local and regional competitions sponsored by the American Guild of Organists when he was 18. He studied at the Eastman School of Music, the New England Conservatory and the Royal College of Music, and became an assistant professor of music at Texas Tech University in 1970.

Mr. Brainard formed Badinage in 1977. Two years later, he earned a doctorate in musical arts from the Juilliard School. In New York, Mr. Brainard was the organist and musical director for the Ethical Culture Society. Of his New York solo debut in Carnegie Recital Hall in 1980, John Rockwell of The New York Times wrote, ''Mr. Brainard's presentation made the best possible case for the music.''

Mr. Brainard is survived by his parents, Robert and Marian Brainard.