He was the eldest of nine children born to the Rev. Ralph and Eliza (Rockwell) Emerson. He married on September 7, 1858 to Adeline Elizabeth Talcott, and they were the parents of three sons and five daughters. After their marriage, they lived with his uncle, the Rev. Joseph Emerson at 427 North Church Street. In the following year, he purchased the house and over the years expanded it into a 30-room mansion, becoming one of Rockford's most familiar landmarks (the house was razed in 1932). As a young adult he began as a teacher. He then removed to Bloomington, Illinois with the intent of studying law, but his close friend Abraham Lincoln dissuaded him from that profession, and Emerson decided to pursue business. He removed to Beloit, Wisconsin and in 1852 removed once again to Rockford where he opened a hardware store in partnership with Jesse Blinn. On March 4, 1854 his future father-in-law Wait Talcott, his brother Sylvester Talcott, and the inventor John H. Manny formed a partnership and created the J.H. Manny & Co., and commenced the manufacture of the John H. Manny Combined Reaper and Mower. This company was paramount to the making of Rockford into a major manufacturing center. In the autumn of that year Ralph Emerson and Jesse Blinn joined as partners, and the company became known as Manny & Co. Shortly after, in September, 1855, the company was sued by Cyrus McCormick for patent infringement. Manny was aided in its defence by Abraham Lincoln, Edward Stanton and Peter Watson who succesfully defended the company and greatly added to its prestige. The company eventually became known as Emerson & Co., and from 1876 to 1895 it was known as the Emerson & Talcott Company. It was then renamed the Emerson Manufacturing Company, and in 1909 it became the Emerson-Brantingham Company. At the time of his death the company was worth $22 million and covered 100 acres. He had many other business interests which included heavy investment in the Rockford Water Power Company, president of the Burson Knitting Company, president of the Burson Manufacturing Company, director of the Rockford Mitten & Hosiery Company, the Nelson Knitting Company, and the Winnebago National Bank. Shortly after the close of the Civil War, he founded the Emerson Institute at Mobile, Alabama, for the purpose of educating African Americans. He was a member of the Second Congregational Church, but otherwise he was not a "joiner", belonging to no lodges and never sought public office. He spent his summers at a residence in Colbrook, Connecticut, a home his grandfather had built in 1793, and at the time of his death he was supervising the building of a new retreat on the Kishwaukee River.