In 1880, the New York State Legislature passed the State Care Act which provided for the removal of all insane persons from almshouses, county asylums, and workhouses to state mental hospitals. The act established a commission which included a psychiatrist president and two lay members and was charged to be responsible for the state mental hospitals. MacDonald was appointed as the president and held the position until 1896 when he resigned in protest of the commission to carry out its responsibilities which were seen by the state hospital superintendents as a threat to their autonomy.
MacDonald, as a member of the New York Medico-Legal Society, worked on the development of the first electric chair, specifically working with other Society members on the composition and placement of electrode on the condemned prisoner.[4][5] He was also an attending physician at the execution of William Kemmler in New York's Auburn Prison on August 6, 1890, the first execution using the electric chair.[6]
He was a professor of mental diseases at the Bellevue Hospital Medical College from 1888 to 1896 and a lecturer at the Albany Medical College from 1892 to 1894. In 1901, MacDonald was asked to examine Leon Czolgosz who had assassinated President McKinley. MacDonald found the prisoner sane and attended Czolgosz’s execution in the electric chair. He attended the autopsy and published his findings in a report. In 1906, MacDonald purchased a private mental hospital, Falkirk Sanatorium, in Central Valley, New York, which he operated for many years.
^"Dr. Carlos F. Macdonald Employed by Bar Association". The New York Times. September 22, 1901. Retrieved 2009-10-31. Leon F. Czolgosz, whose trial for the assassination of President McKinley will begin next Monday, was examined as to his sanity for one hour this afternoon by Dr. Carlos F. Macdonald of New York, the eminent alienist, who was for years the Chairman of the State Board of Lunacy Commissioners.
^Terry S. Reynolds, Theodore Bernstein, Edison and "The Chair", Technology and Society Magazine, IEEE (Volume:8 , Issue: 1) March 1989, pages 19 - 28
^Mark Essig, Edison and the Electric Chair: A Story of Light and Death, Bloomsbury Publishing USA - 2009, pages 225
^Markus Hedrich, Medizinische Gewalt: Elektrotherapie, elektrischer Stuhl und psychiatrische »Elektroschocktherapie« in den USA, 1890-1950. Transcript, Bielefeld, 2014, pages 89-138 (in German)