On leaving college he went into the nursery business, not having physical stamina sufficient to prosecute his studies for the ministry, as intended. In this business he continued directly for eighteen months, and partially for five or six years.

In the Fall of 1847, he commenced teaching in the public schools in Cuyahoga Falls, and in the following Spring established a private school, the Cuyahoga Falls Seminary. At the end of that year he was elected Superintendent of Public Instruction and principal of the high school. He continued his seminary, having assistants, and the privilege being allowed him of spending a portion of his time in the management of that establishment. In the Fall of 1849, he came to Cleveland and was appointed principal of the Rockwell street grammar school, where he remained seven years, bringing up the school from a low pitch to rank among the foremost in the city. His salary, when he began to teach in Cleveland was but five hundred dollars, and out of this he had to provide for two families, his own and that of his parents. To add to his small stipend, he taught evening school, and took agencies in the vacation. At the same time he was repeatedly offered other situations at better salaries, and was invited to become the principal of a State Normal school. He tendered his resignation as principal of the Rockwell street school, but was induced to remain on promise of increase of salary. Finally, becoming weary of that hope deferred that maketh the heart sick, he resigned and was engaged at a much higher salary, to establish, under the patronage of an association of leading citizens, the Cleveland Academy. This enterprise was very successful, and the position pleasant, a fine corps of assistants being gathered around him.

After two years labor in this position, some gentlemen connected with the property on University Heights, requested him to engage in the enterprise of a school on the Heights, in the building erected for a college under president Mahan, but which now lay unfinished and unoccupied, the college scheme having failed. They offered rent and grounds free, but he refused, until they agreed to sell him the whole property for a nominal sum, if he could acquire a clear title, the ownership having become badly involved by the failure of the college. This he eventually accomplished after much labor, and took possession of the property in 1856.

The task was a gigantic one to a man like Mr. Humiston, with limited funds and uncertain health. The building was unfinished and needed considerable expenditure to put it in shape for occupation. The location though very promising in the distant future, was then very inconvenient of access, and was therefore objectionable. But Mr. Humiston possessed a determined will and he set to work without delay. He borrowed money, fitted up a portion of the building, and opened the Cleveland Institute with strong hopes for the future, but gloomy prospects in the present.

About the middle of the second year the building took fire and a large portion of the interior was destroyed. The school was closed for six months, and with characteristic energy Mr. Humiston went to work to repair damages, enlarging the building, and again involving himself in debt to meet the expense. Success crowned his enterprise. The number of scholars increased rapidly, and again the building had to be enlarged and improved.

The institute was continued ten years, and the gross income in its later years ranged from $20,000 to $31,000 per year. During nearly the whole time Mr. Humiston taught himself, and usually five hours out of the six devoted to studies. At the same time he gave medical lectures at the Western Homoeopathic College, and managed all the affairs of the institute, keeping no agent or steward. He purchased and fitted up in the institute a fine chemical and philosophical apparatus, collected a good library and several valuable cabinets of specimens in natural history, geology, and mineralogy. The corps of teachers was large and of superior talents.

In 1868, Mr. Humiston, considering that he had earned a respite from his arduous and unremitting labors, accepted an offer from some gentlemen desirous of establishing a Homoeopathic Hospital, and sold his building' with half the adjoining grounds for $35,000. He then accepted the tender of the agency of the American Missionary Association in Great Britain, and early in 1869 left for Europe, having previously visited the South in order to acquaint himself with the condition of the freedmen, whose cause he designed especially to present. After a year or more spent in this work he designs visiting the remainder of Europe, North Africa, and the Holy Land.

Mr. Humiston has, since 1859, held the position of Professor of Chemistry and Toxicology in the Western Homoeopathic College, and has given ten courses of lectures in that institution. Each year he insisted on resigning, but the resignation has always been refused. On closing his educational career he again resigned, but the college again refused to accept his resignation, promising to supply his place temporarily during his absence in Europe.

The distinguishing characteristic of Mr. Humiston is his strong will, and this is well exemplified in the fact that although born with a constitutional fierce thirst for liquor, he has been able to continue in right habits of temperance through all temptation, though at the cost of many powerful struggles with his inordinate cravings. He is a man of strong religions convictions, and has been so from his youth up. For many years he was connected with the Methodist church on University Heights. As an educator he ranks among the best in the State, and was held in deservedly high esteem by those who had themselves been taught by him, or whose children had been brought up under his tuition.