Locke returned to Howard University as the chair of the department of philosophy. During this period, he began teaching the first classes on race relations, leading to his dismissal in 1925. After being reinstated in 1928, Locke remained at Howard until his retirement in 1953. Locke Hall, on the Howard campus, is named after him.
Locke promoted African-American artists, writers, and musicians, encouraging them to look to Africa as an inspiration for their works. He encouraged them to depict African and African-American subjects, and to draw on their history for subject material.
Locke was the guest editor of the March 1925 issue of the periodical Survey Graphic titled “Harlem, Mecca of the New Negro”, a special on Harlem and the Harlem Renaissance, which helped educate white readers about its flourishing culture. In December of that year, he expanded the issue into The New Negro, a collection of writings by African Americans, which would become one of his best known works. A landmark in black literature (later acclaimed as the “first national book” of African America), it was an instant success. Locke contributed five essays: the “Foreword”, “The New Negro”, “Negro Youth Speaks”, “The Negro Spirituals”, and “The Legacy of Ancestral Arts”.
Locke’s philosophy of the New Negro was grounded in the concept of race-building. Its most important component is overall awareness of the potential black equality; no longer would blacks allow themselves to adjust themselves or comply with unreasonable white requests. This idea was based on self-confidence and political awareness. Although in the past the laws regarding equality had been ignored without consequence, Locke’s philosophical idea of The New Negro allowed for fair treatment. Because this was an idea and not a law, its power was held in the people. If they wanted this idea to flourish, they were the ones who would need to “enforce” it through their actions and overall points of view.
While his own writing was sophisticated philosophy, and therefore not popularly accessible, he mentored others in the movement who would become more broadly known, like Zora Neale Hurston.
Locke was a member of the Bahá’í Faith and declared his belief in Bahá’u’lláh in 1918. It was common to write to ‘Abdu’l-Bahá to declare one’s new faith, and Locke received a letter, or “tablet”, from ‘Abdu’l-Bahá in return. When ‘Abdu’l-Bahá died in 1921, Locke enjoyed a close relationship with Shoghi Effendi, then head of the Bahá’í Faith. Shoghi Effendi is reported to have said to Locke, “People as you, Mr. Gregory, Dr. Esslemont and some other dear souls are as rare as diamond.”
Locke was gay, and may have encouraged and supported other gay African-Americans who were part of the Harlem Renaissance. However, he was not fully public in his orientation and referred to it as his point of “vulnerable/invulnerability”, taken to mean an area of risk and strength in his view.
After his retirement from Howard University in 1953, Locke moved to New York City. He suffered from heart disease, and after a six-week illness died at Mount Sinai Hospital on June 9, 1954.
Locke was cremated, and his remains turned over to Dr. Arthur Fauset, an anthropologist who was a major figure in the Harlem Renaissance. Fauset was Locke’s close friend, and executor of his estate. Fauset died in 1983, and the remains were given to his friend, Reverend Sadie Mitchell. Mitchell ministered at African Episcopal Church of St. Thomas in Philadelphia. Mitchell retained the ashes until the mid-1990s, when she asked Dr. J. Weldon Norris, a professor of music at Howard University, to take the ashes to Washington, D.C. The ashes then resided at Howard University’s Moorland–Spingarn Research Center until 2007. Concerned that the human remains were not properly cared for, the ashes were given to Howard University’s W. Montague Cobb Research Laboratory, which had extensive experience handling human remains. Locke’s ashes, which were stored in a plain paper bag in a simple round metal container, were transferred to a more appropriate small funerary urn. They were locked in a safe to keep them secure.