[2] He was of Welsh and English descent and was the only child of Annie Belinda Manifold (1854–1935) and Aquilla Asbury Reese Jr. (1845–1914).

In addition to his farmland work, Reese raised frogs that he sold to restaurants in the Baltimore area.

[6] Jobless in 1919, Reese formed a new business called the R&R Candy Company that he operated from an old canning factory located in Hummelstown, Pennsylvania, where he manufactured milk chocolate covered almonds and raisins, selling them to local stores.

[7] Reese knew he needed high-quality manufacturing equipment in order to boost the potential of his Hummelstown, Pennsylvania, candy business.

[7] In 1921, Reese's father-in-law purchased a home at 18 E. Areba Avenue in Hershey, Pennsylvania, for his son-in-law's growing family.

[9] On the side, working from the basement of his Areba Avenue home, he made a variety of confectionery products including hard candy, chocolate covered nuts and raisins, mints as well as two popular milk chocolate covered caramel-coconut candy bars that he invented:[10] The ingredients for both bars included fresh grated coconut, caramel, molasses, cocoa butter and honey.

To promote sales, Reese set up special coating tables in the front display windows of large, downtown department stores and had his employees coat candies in full view of shoppers passing by while other employees handed out freshly made samples.

Sales of the penny peanut butter cup helped Reese pay off the mortgages on both his house and factory by 1935.

During World War II, economic constraints and scarcity of materials led him to discontinue his other candies.

[15] After a short illness, H. B. Reese died of a heart attack[16] eight days before his 77th birthday, on May 16, 1956, at the St. Mary's Medical Center in West Palm Beach, Florida, where he had been vacationing.

[8] In 1969, only six years after the Reese/Hershey merger, Reese's Peanut Butter Cups became the best-selling product of The Hershey Company.