Gayley soon relocated to Ireland with his mother, Sarah, where he was educated at Blackheath school and the Royal Belfast Academical Institution.

Gayley earned his Doctorate at the University of Michigan and briefly served there as an Assistant Professor of English and Latin.

While at Michigan, Gayley: (a) composed the Michigan college songs, "The Yellow and Blue" and "Laudes atque Carmina"; (b) developed a love of Shakespeare and poetry; (c) studied one year abroad at the University of Giessen, Hesse-Darmstadt, Germany (emphasizing German, medieval European history, and Modern French History); and (c) accepted what he regarded as a call (within ten minutes of receiving it) to teach in California.

[1] He served as University Examiner, Head of the English Department, Dean of Faculties, visiting professor at Oxford, and was a Director of the Commercial Bank of Berkeley.

Occasionally, Gayley's lectures were relocated to the outdoor Greek theatre to accommodate overflow students and guests.

A persistent advocate of education and idea-sharing, Gayley was instrumental in the development of the University Extension, the College of Commerce, building the Senior Hall, the Stephens Union (on the model of the Oxford Union), bringing Psi Upsilon to Berkeley, and establishing the student volunteers' Ambulance Corps.

Gayley initiated the Berkeley Canterbury Club as a forum to discuss the application of Christian principles to everyday life; and his academic course, The Bible in English Literature, was popular among students.

[2] In 1943, former student Benjamin P. Kurtz authored the professor's biography, Charles Mills Gayley: The Glory of a Lighted Mind.

With the American Civil War threatening to curtail money for foreign missionaries, Charles' father got them passage on a ship to Tengzhou, where they established a new mission.

But with the civil war still in progress, Charles' mother Sarah decided first to sail for Ireland, to pay her respects to her dead husbands family.

The arrival of his great-uncle changed his aspirations, declaring that Charles, as an American citizen, should be educated in the United States.

With his mother eventually giving her approval, Gayley left Ireland for the University of Michigan, there to study law.

He was also surprised to win a competition to write a college song for Michigan, receiving the sum of $10 for his composition "The Yellow and Blue".

After a speech of his praising Gladstone's Home Rule Bill was received favourably, it was arranged that Gayley would meet with Irish liberals in London.