Brown University has their portrait collection online! And so finding out about the painting and this person was a breeze.
In short, Harold Brooks Tanner, received his undergraduate degree from Brown in 1909, went to Harvard for law school, and had a long law career in RI. He served as a Trustee from 1929 till his death in 1968 -- twice serving as Chancellor.
Follow this link to see this portrait in stunning color, and for more info on the painting and person:
http://dl.lib.brown.edu/portraits/display.php?idno=257
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