John Hutchings (John II) Sealy, entrepreneur, the son of Rebecca (Davis) and John Sealy, was born in Galveston on September 15, 1870. A member of the first graduating class of Ball High School in Galveston in 1887, Sealy received his diploma from Princeton University in 1891 as one of that school's youngest graduates to date. His father died in 1884, and upon graduation Sealy assumed the role of full partner in the Hutchings-Sealy Bank, of which his father was a cofounder. Although he was only thirty when the Galveston hurricane of 1900 struck, Sealy was a leader among Galveston businessmen in the management of immediate relief operations as well as in long-range planning and rebuilding. He served as chairman of the Finance Commission and was instrumental in the construction of the seawall and grade-raising of the city. In 1901 Sealy became a senior partner of the Hutchings-Sealy Bank and was elected to succeed his uncle George Sealy as the president of both the Gulf, Colorado and Santa Fe Railway and the Galveston Wharf Company. Gifted with considerable business acumen, he diversified his financial interests and in 1911 bought several oil properties which he used to found Magnolia Petroleum Company, later absorbed by Standard Oil Company of New York and known today as Mobil Oil. He also was vice president and a one-fifth owner of American Indemnity and cofounded the Galveston Hotel Company. His other holdings included the International Creosoting and Construction Company, Galveston Ice and Storage Company, Texas Indemnity Company, and Union Passenger Company.
Sealy endeared himself to the Galveston community through his philanthropic and civic endeavors. Best known for the lifelong support he provided to the John Sealy Hospital, named in honor of his father, Sealy's other contributions included serving as treasurer for the Diocese of Texas of the Episcopal Church, trustee of the Galveston city schools, founding board member and president of the Rosenberg Library, and member of the University of Texas Board of Regents. He also helped support and served on the boards of both the Galveston Orphan's Home and the Letitia Rosenberg Woman's Home. Throughout his lifetime Sealy underwrote operating deficits of the John Sealy Hospital and also paid for remodeling, expansion, and improvements. It is estimated that he and his sister, Jennie Sealy Smith, contributed $1 million of their personal funds to the original facility and a women's hospital, built in 1915–16. To ensure the ongoing work of the hospital, they established the Sealy and Smith Foundation for the John Sealy Hospital in 1922. John Sealy II, said to be the wealthiest man in Texas, died unexpectedly on February 19, 1926, in Neuilly, France, on his way back from Italy, where he had gone to be treated for malignant carbuncles. About 4,000 Galvestonians, representing all levels of the island's citizenry, met the train carrying his body back home for burial. Having never married, he left the major portion of his fortune to the Sealy and Smith Foundation for the John Sealy Hospital.