He was born to Francis Hollins and Elizabeth Coles Morris. Hollins, a native New Yorker educated in private schools was married to socialite Evelina Merseole Knapp on January 25, 1877. The couple had four sons, Harry B. Jr,McKim (Kim), John K. (Jack), Gerald V. and a daughter, Marion. Colloquially known as HBH or HB. He was notable in New York society life. Members of the Hollins family were such prominent figures and were regularly mentioned in the New York Times social diary.

Hollins resided between Manhattan at his multiple town residences and at his 600-acre (2.4 km2) country estate, Meadow Farm in East Islip, Long Island. Hollins entertained family and friends at Meadow Farm each summer and early autumn; these renowned guests to summer at the estate included Hollins' friend, the future King Edward VIII. Meadow Farm is also believed to be the birthplace of his children. His family's residences, mainly the East Islip mansion were said to contain many valuable paintings and rare objects of art.

Hollins began business as a marine insurance broker, and became a banker in 1888. At one time he was a partner of Fernando Iznaga, whose sister Maria Consuelo Iznaga Clement was the Dowager Duchess of Manchester. In fact, he was along with close friend William K. Vanderbilt, the executors of Iznaga's will. Along with Eugene Zimmerman of Cincinnati, Ohio, the father of the Duchess of Manchester, had owned an interest in a number of properties in the Midwest. These properties included Superior Colliery Company and Superior Development Company.

J. P. Morgan and H. B. Hollins were also business partners and the closest of friends until the former's death. In fact Morgan's offices were located across the street from H. B. Hollins & Co.'s exclusive banking offices, at the southwest corner of Wall and Broad Streets. On November 13, 1913, H.B. Hollins & Co., one of Wall Street's most highly regarded houses failed in debt of $5,000,000. The failure of the house was related to a number of issues including the Company letting their Stock Exchange business go adrift, paying more attention to floatation of new companies and to banking operations in addition to their expenses boring them down. After the news of the firm failure had spread through the financial district, Hollin's attorney's Beekman, Menken & Griscom released a press statement downplaying the collapse:

A large portion of the securities was understood on the Street to represent a number of companies in Mexico that were adversely impacted by political turmoil south of the border at the time. These enterprises were thought to include Mexican Crude Oil, Asphaltic Products Company, and United States Asphalt Company. Harry B. Hollins belonged to the Union Metropolitan, South Side Sportsmen's, Knickerbocker, New York Yacht, Meadow Brook, Racquet and Tennis, Riding, and Garden City Golf Clubs, also the Automobile Club of America.

After Hollins' bankruptcy, Meadow Farm, the country manor, was sold to Charles L. Lawrance along with 116 acres (0.47 km2) bordering the Great South Bay and Champlin Creek. The family renovated one of the farmhouses on the northern portion of the approximately 480 acres (1.9 km2) remaining to which they relocated. After the death of Mrs. H. B. Hollins, a month after her husband, her daughter Marion as the administrator of the estate sold most of the property not utilized by the family.

Meadow Farm was demolished in 2002/03 as part of the Harbour View project. This project was completion of The Moorings, a wealthy gated community by the subdividing Meadow Farm's remaining 16 acres (65,000 m2) into 11 lots. The purchaser of the 5.88-acre (23,800 m2) parcel (now 150 Meadowfarm Road) containing Meadow Farm learned the cost of refurbishing the mansion would have well exceeded $1 million and opted to replace it with a newer estate. According to a New York Times article written in 1999, the new estate's owner planned to salvage marble fireplaces, panelling and other appurtenances from the mansion.

Remnants of Hollins' Meadow Farm can still be found off of Dock Road, including the original gates now leading to a small community named after the family, Hollins Estates. The once private road leading to the manor house was named Hollins Lane. The Hollins' stable and clock tower remains as a residential house at 37 Blackmore Lane. A carriage house, located west of Meadowfarm Road and last used as a residence, was demolished in the late 1980s to make way for a subdivision. At 35 Blackmore Lane is what was believed to have been the estate manager's (Blackmore) house, which had been moved from another location nearby.

At 42 Blackmore Lane is a structure on a 5-acre (20,000 m2) parcel which also belonged to Hollins. It was the renovated farmhouse they relocated to after parting with Meadow Farm. Harvard Class books from the 1930s were found in the house in the 1980s - a member of the Hollins family was pictured in those books.

A company, Yarmouth Estates of Bay Shore, New York, has purchased the house at 42 Blackmore and is requesting a subdivision. Harry Hollins Jr.'s estate house, designed by the architectural firm of Cross & Cross and built in 1907, remains at 18 Crick Holly Lane and Gerald Hollins' home remains at 180 Bayview Avenue. The carriage house for Gerard Hollins' house still stands at 158 Bayview Ave and is now used as a private residence. Gerald Hollins later built a home on White Oak Lane, which still stands and is now the visitor's center for the South Shore Nature Center.