Colonel Michaux had earned a bachelor's degree from the University of Maryland, College Park in 1962, and also graduated from the Naval War College in Newport, R.I., in 1966 and the Army War College in 1969.
He returned to McDonogh as director of development and in 1971 was appointed the school's first president and executive head.
Colonel Michaux led the effort in 1975 that transformed McDonogh from a military school to a coeducational one.
"In 1971 we formed a committee of faculty and staff to look at the school and suggest improvement," Colonel Michaux told The Evening Sun in a 1976 interview.
"Their biggest recommendation was that we become coeducational. They thought it would be a more realistic atmosphere. The majority of our students were going to coeducational colleges — every year there were fewer men's colleges to choose from — and many of them used to come back and say they wished they'd made that adjustment before college," he said.
"We also had interest from parents and alumni who wanted to send their daughters to McDonogh," he said, explaining that the policy was to accept the best-qualified applicants, boys or girls.
"That was the first time in 98 years that McDonogh students wore civilian clothes," said Ms. Gonzales. "He believed the time had come and that they'd do better being a civilian school rather than a military one."
"Lud was a very focused person and he served McDonogh well during an important and complicated period of time. He was a bridge," said George S. Wills, a retired Baltimore public relations executive and McDonogh alumnus. "He was both quiet and effective."
Eileen S. Toohey was a member of the first coeducational class that entered McDonogh in the fall of 1975.
"My impression of him was that he was a very strong leader in both stature and appearance and the way he talked. He could make decisions and always got right to it," said Ms. Toohey, a senior development associate at McDonogh.
"When you were in his company, you always stood up straight because he had been a career Marine officer," said Ms. Toohey. "He was a very friendly man but if you got into trouble, he'd go knee-to-knee with you in a very direct manner. And in the end, he'd break into a smile, and you knew that things were all right again."
After retiring from McDonogh in 1976, he and his wife, the former Cornelia Smith, whom he married in 1949, moved to Scottsdale, Ariz., where he worked as a real estate broker.
They returned to Rodgers Forge a decade later. Colonel Michaux volunteered at McDonogh and the Greater Baltimore Committee, participating in its College Bound Program and helping to raise $25 million for city public school graduates to attend college.
He was also a communicant of the Episcopal Church of the Redeemer, where he was a member of its vestry and served on various other committees.
Colonel Michaux enjoyed playing tennis.
His wife died in 1995.
A memorial service will be held at 11 a.m. June 20 at McDonogh's Tagart Memorial Chapel, 8600 McDonogh Road, Owings Mills.
In addition to his daughter, Colonel Michaux is survived by a son, Randolph M. Michaux of Ashburn, Va.; another daughter, Beverly Michaux of Mount Washington; a brother, Bernard B. Michaux of El Macero, Calif.; four grandchildren; and seven great-grandchildren. Another daughter, Priscilla Roosevelt Levindowski, died in 1992.