The preparation program for the Jesuits can last up to a dozen years, and Tom started his novitiate, where he said his position "quite corresponds to that of a cadet in the army," in England. Back in America, he studied philosophy and taught at St. Louis University, a Jesuit school founded in 1818. There he preferred public speaking to teaching, bit he made a strong impression on his students, several of whom followed him into the Jesuits.

As the son of a leading national hero, Tom Sherman was something of a celebrity, a man set apart. In 1889, he was ordained to the priesthood, but in a separate ceremony from the rest of his class. His mother's close friend, Archbishop Patrick Ryan of Philadephia, performed the ordination. The event was national news, and Father Sherman looked forward to a promising career.

While most Jesuits take up teaching or parish work after ordination, Sherman seems to have written his own ticket as a popular lecturer. His biographer Joseph Durkin writes that he "had a flair for the dramatic and an acute sense of the theatre." One peer described him as "always hungry" for a podium. No doubt his name and background helped draw crowds.   

And draw crowds he did. In time, however, he butted heads with his superiors, who felt that fame might be going to his head. Durkin describes him as "a high-strung individualist of an extreme refinement of nature and a disposition unusually sensitive." Ordered to take a break from the lecture circuit, he went over his superiors' heads to Rome, and got a leave of absence from the Jesuit order. During the Spanish-American War, he obtained a chaplain's commission without consulting the Jesuits.

For several years, Sherman drifted from one Jesuit assignment to another until he suffered a nervous breakdown in his early fifties. Institutionalized for several years, he traveled around the country from one Jesuit community to another. "Having served in six provinces," he wrote a friend, "I am attached to none." In a fit of despair he wrote, "I am utterly at a loss what to do...no peace is possible for me."

In the fall of 1914, Sherman formally withdrew from the Jesuits. For several years, unattached to any diocese or religious order, he wandered around the country before settling down in Santa Barbara, California, where family members looked after him. For much of this time, Durkin writes, he was "allergic to the mention of the word 'Jesuit.'"

Just before his death at age seventy-seven, however, Father Thomas Ewing Sherman reconciled with the Jesuits and renewed his vows. After many years of unrest, General Sherman's son died a Jesuit. He was buried in their cemetery at Grand Couteau, Louisiana. Interred next to him is Father John Salter, a nephew of Alexander Stephens, Vice President of the Confederate States of America.