
In 1888 he married Elizabeth Walker and together they had four children, two sons (Hugh and Douglas) and two daughters (Irene and Kathleen). In 1889 Sir Robert Anderson and Sir Joseph Ward formed the Mercantile Firm of J G Ward and Co. He took a leading part in the development of Southland serving on many of its local bodies and societies, and also became prominent in dominion financial circles as Director of numerous leading New Zealand companies.
Sir Robert was a generous man and made a large contribution to the founding of the Southland Museum. He also equipped the Otakaro Park Children’s playground, provided the Civic Theatre with a grand piano, and gave their former family home on the corner of Gala Street and Queens Drive to the Plunket Society.

Sir Robert Anderson died in 1942, at the age of 76 and Lady Anderson in 1951, at the age of 86. The children carried out their parents’ wishes by donating the home and grounds of the then named 'Victoria Park', to the city of Invercargill.
In recognition of the gift, the City Council decided to rename the property Anderson Park and established a civic gallery in the former home. On the opening of the gallery on 27th October 1951, Mr Hewat declared that as the Andersons were known for their generosity that it was fitting that their names should be kept before the public at such a fine place as Anderson Park.