Stuart H. Johnson Jr., 58, a Washington attorney and a former counsel to the House Judiciary Committee and chief counsel of the Antitrust Subcommittee, died June 12 of injuries he received in a riding accident in Middleburg, Va., on May 16.

Mr. Johnson, who was born in Oyster Bay, N.Y., earned bachelor's and law degrees at Yale University. He was a Japanese language officer in the Army during World War II and served in the Pacific and later in Japan.

He was an attorney in New York City for 10 years until 1962, when he moved to Washington as counsel of the House Judiciary Committee and the Antitrust Subcommittee. In 1966, Mr. Johnson resigned from Capitol Hill and entered a private law practice here.

He received a citation from the Federal Bar Association for chairing its committee on model rules of evidence.

Survivors include his wife, the former Katharine Southerland Miller, of Washington, and two daughters, Wilhelmina and Eunice, all of Washington; two sons, Stuart, of New York City, and Thomas, of Washington; five stepdaughters, Amey Miller, of Chapel Hill, N.C., Abigail Miller and Clare Miller Watsky, both of San Francisco, Marion Miller, of Kneeland, Calif., and Katharine Miller, of Boston; a brother, Coit, of Dublin, N.H., and two sisters, Eunice Winslow, of New York City, and Priscilla McMillan, of Cambridge, Mass.