John Mercer emigrated from Ireland in 1720. His first wife was Catherine Mason. His second wife was Anne Roy. Mercer lived at Marlborough Point. This portrait is very similar to another one by John Hesselius. It is possible that Hesselius painted the subject twice and that this portrait has overpaint or was heavily restored. This may also be a copy of the original portrait by Hesselius.
Dimensions: 27 x 22 1/2 in. (68.58 x 56.73 cm.)
The subject wears a jacket over a dark waistcoat and a gray wig. He is turned three-quarters to his left. His right hand holds a piece of paper.