Brother Donald Kelly, F.M.S., a member of the Marist Brothers of the Schools for 55 years, died Aug. 3, at his residence in Poughkeepsie. He was 74.

Born in the Bronx, he attended St. Helena H.S. before entering the Marist Juniorate in Esopus, N.Y., in 1957. He professed his final vows in 1967.

After completing religious and academic studies at Marist College, Poughkeepsie, he taught at Christ the King H.S., Middle Village, 1966-79.

He also served as a teacher at Msgr. Edward Pace H.S., Miami Gardens, Fla., 1979-82, and Marist H.S., Chicago, Ill., 1982-84, and as a math professor at Marist College, Poughkeepsie, 1986-2015.

He earned a doctorate in mathematics from Brooklyn Polytech in 1993.

He is survived by his sisters, Patricia McCarthy, and Eileen Bohan.

Burial followed at the Marist Brothers’ Cemetery in Esopus.