Jackson Ward Wisner, 76, a retired Montgomery County school teacher, died Thursday after apparently suffering a heart attack while driving his car near his home in Rockville. The car crashed into a tree.

Mr. Wisner had been with the county school from 1937 until retiring in the early 1960s. Most of his service was at Richard Montgomery High School in Rockville. He taught mathematics, metal work and airplane welding.

During World War II, Mr. Wisner was given leave from the school system to work for the U.S. Tariff Commission.

Born in Hagerstown, he grew up in Baltimore and received a degree in mechanical engineering from the University of Maryland.

After coming to this area in 1924, he was a builder and contractor and at one time operated a hardware and garden shop on Rockville Pike.

Mr. Wisner was a past master of Montgomery Lodge No. 195 of the Masons and designed its building in Rockville.

For many years he sang in the choir of Christ Episcopal Church in Rockville.

He is survived by his wife, Sody McKenzie Wisner, of the home; two sons, Dr. Jackson Ward Wisner Jr., of Wappingers Falls, N.Y., and William McKenzie Wisner, of Rockville; a sister, Katherine Wisner Millis, of Cleveland, and 11 grandchildren.