Thanks to loans from the family of lifelong friend Andrew Mellon, by 1880, Frick bought out the partnership. The company was renamed H. C. Frick & Company, employed 1,000 workers and controlled 80 percent of the coal output in Pennsylvania.
Frick, at the suggestion of his friend Benjamin Ruff, formed the exclusive South Fork Fishing and Hunting Club high above Johnstown, Pennsylvania. The charter members of the South Fork Fishing and Hunting Club, assembled by Henry Clay Frick, were: Benjamin Ruff; T. H. Sweat; Charles J. Clarke; Thomas Clark; Walter F. Fundenberg; Howard Hartley; Henry C. Yeager; J. B. White; Henry Clay Frick; E. A. Meyers; C. C. Hussey; D. R. Ewer; C. A. Carpenter; W. L. Dunn; W. L. McClintock; A. V. Holmes.
The sixty-odd club members were the leading business tycoons of Western Pennsylvania, and included among their number Frick’s best friend, Andrew Mellon, his attorneys Philander Knox and James Hay Reed, as well as Frick's sometime business partner Andrew Carnegie. The Club members created what was at that time the world's largest earthen dam, behind which formed a private lake called Lake Conemaugh. Less than downstream from the dam sat the city of Johnstown, and not incidentally, Carnegie Steel's chief competitor, the Cambria Iron and Steel Company, which at that time boasted the world's largest annual steel production.
Poor maintenance, unusually high snowmelt and heavy spring rains combined to cause the dam to give way on May 31, 1889, resulting in the Johnstown Flood. When word of the dam's failure was telegraphed to Pittsburgh, Frick and other members of the club gathered to form the Pittsburgh Relief Committee for tangible assistance to the flood victims, as well as determining to never speak publicly about the club or the flood. This strategy was a success, and Knox and Reed were able to fend off all lawsuits that would have placed blame upon the club’s members. Although Cambria Iron and Steel's facilities were heavily damaged, they returned to full production within a year and a half.
Frick, realizing what was happening, attempted to rise from his chair while Berkman pulled a revolver and fired at nearly point-blank range. The bullet hit Frick in the left earlobe, penetrated his neck near the base of the skull, and lodged in his back. The impact hurled Frick off his feet, and Berkman fired again, again striking Frick in the neck and causing him to bleed profusely. Carnegie Steel vice president (later, president) John George Alexander Leishman, who was with Frick, was then able to grab Berkman’s arm and deflect a third shot, saving Frick's life.
Although wounded, Frick rose and tackled his assailant. All three men crashed to the floor, where Berkman managed to stab Frick four times in the leg with the pointed steel file before finally being subdued by other employees, who had rushed into the office. As the police entered the room, guns drawn, Frick reportedly yelled, "Don't shoot! Leave him to the law, but raise his head and let me see his face." Frick pointed to Berkman, who was chewing on a capsule of Mercury(II) fulminate which might have exploded near Frick, Berkman, and everybody else in the office. For more than two hours doctors probed for the bullets; Frick reportedly refused anesthesia so he could help guide their efforts.
Frick was back at work in a week; Berkman was charged and found guilty of attempted murder. Berkman's actions in planning the assassination clearly indicated a premeditated intent to kill, and he was sentenced to 22 years in prison. He eventually served a total of fourteen years, and under pressure from supporters in the labor movement, including the forming of The Berkman Defense Association, was pardoned in 1906.
Negative publicity from the attempted assassination resulted in the collapse of the strike. Two thousand five hundred men lost their jobs, and most of the workers who stayed had their wages halved.
In 1881, Frick married Adelaide Childs of Pittsburgh. In 1882, after the formation of the partnership with Andrew Carnegie, Frick and his wife bought Clayton, an estate in Pittsburgh. They moved into the estate in 1883. The Frick children, Childs, and Helen, were born in Pittsburgh and were raised at Clayton. Two additional children, Henry Clay Frick Jr. and Martha Frick, died in infancy or childhood. In 1904, he built Eagle Rock, a summer estate at Prides Crossing in Beverly, Massachusetts on Boston's fashionable North Shore. The 104-room mansion designed by Little & Browne would be razed in 1969.
Frick was an avid art collector whose wealth allowed him to accumulate a significant art collection. By 1905, Henry Clay Frick's business, social, and artistic interests had shifted from Pittsburgh to New York. He took his art collection with him to New York, and served on many corporate boards, which brought him considerable opportunity to continue his lifelong business machinations.
For example, as a board member of the Equitable Life Insurance Company, Frick attempted to wheedle the removal of James Hazen Hyde (the founder's only son and heir) from the United States to France by seeking an appointment for him to become United States Ambassador to France. Frick had engaged a similar stratagem when orchestrating the ouster of the man who had saved his life, John George Alexander Leishman, from the presidency of Carnegie Steel a decade beforehand. In that instance, Leishman had chosen to accept the post as ambassador to Switzerland. Hyde, however, rebuffed Frick's plan. Hyde did, nonetheless, move to France, where he served as an ambulance driver during World War I and lived until the outbreak of World War II. Ironically, while in France, Hyde married Leishman's eldest daughter, Marthe.
In 1910, Frick purchased property at Fifth Avenue and 70th Street to construct a mansion, now known as The Frick Collection. Built to a massive size and covering a full city block, Frick told friends he was building it to "make Carnegie's place look like a miner's shack." In 1914, Frick built the William Penn Hotel in Pittsburgh, Pennsylvania.
To this day, the Frick Collection is home to one of the finest collections of European paintings in the United States. It contains many works of art dating from the pre-Renaissance up to the post-Impressionist eras. In addition to paintings, it also contains a beautiful exhibition of carpets, porcelain, sculptures, and fine furniture; and is a wonderful example of design and architecture. Frick continued to live at both his New York mansion and at Clayton until his death.
Many years after her father's death, Helen Clay Frick returned to Clayton in 1981, and lived there until her death in 1984. After extensive restoration, this property was also opened to the public in 1990 as the Frick Art & Historical Center.