Emmerson was born at Chester le Street, County Durham, and having studied at Newcastle under William Bell Scott, lived in Northumberland all his life, variously at Ebchester, Bywell, Whickham, Morpeth and Cullercoats. He derived his subject matter almost exclusively from his native county, and exhibited 54 pictures at the Royal Academy between 1851 and 1893. He enjoyed a great reputation in the north east, and many of his pictures entered family collections there. One of his patrons was the first Lord Armstrong, whose portrait he painted seated in the dining room inglenook at Cragside.