He graduated with an Bachelor of Arts in physics 1882 and was awarded a graduate fellowship at the university for a year, which he spent at the Princeton laboratory. Three years later he was awarded a Doctor of Philosophy in physics with a thesis on "Doppler Determination of the Rotation Period of the Sun for Various Heliocentric Latitudes.".
In 1883 he traveled for a semester overseas to study physics in Berlin, returning in 1884 to attend graduate school at the Johns Hopkins University. After a term with an associateship in physics at Johns Hopkins, he became an assistant instructor of physics at Haverford College from 1888–1892. During his last year at Haverford, Henry Crew was married to Helen C. Coale, a graduate of Bryn Mawr College.
He then joined the staff of the Lick Observatory in 1892, but soon found himself entangled in the political atmosphere.
That year he was awarded the position of Fayerweather professor of physics at Northwestern University, which he accepted. He would remain at that post until he retired 41 years later in 1933.
In 1930, he was granted leave from Northwestern to accept an appointment at the Century of Progress International Exposition staged in Chicago 1933–1934, where he was chief of the division of basic sciences. During his career, Henry wrote a number of works on spectroscopy, the history of science, and biographies of physicists, producing 123 articles and 12 books
He was elected president of the American Physical Society in 1909.
He served as the president of the History of Science Society in 1930. In 1941 he was awarded the Oersted Medal by the American Association of Physics Teachers.
Member National Academy Sciences, American Physical Society (president 1909), Illinois Academy Sciences (president 1912), American Philosophical Society, American Association University professors (president 1929-1930), History of Science Society (president 1930). Clubs: University (Chicago and Evanston).
Married Helen C. Coale, July 17, 1890. Children: Alice H., Mildred, William H. Instructor.