Robert Louis Stevenson | Robert De Niro | Robert E. Lee | William Howard Taft | Robert Mugabe | Robert Redford | Robert Burns | Robert Bosch GmbH | Robert | Robert A. Heinlein | Robert Schumann | Robert Browning | Robert Rauschenberg | Robert Plant | Robert Altman | Robert Mitchum | Robert Frost | Robert Southey | Robert F. Kennedy | Robert Maxwell | Robert Graves | Robert E. Howard | Robert Fripp | Robert Fisk | Robert Rodriguez | Robert Motherwell | Robert Lowell | Robert Johnson | Robert Duvall | Robert Boyle |
Portraits for clients outside these Yale commissions included Senator Robert Taft, Governor John Davis Lodge, and Presidents William Howard Taft and Herbert Hoover.
Gilligan narrowly lost his re-election bid to the Ninetieth Congress in 1966 to Republican Robert Taft Jr. after the Republican-controlled Ohio General Assembly redrew his district to favor the Republican Party.
Major collections he utilized included the papers of Dwight D. Eisenhower and Robert Taft, the two main Republican contenders for the nomination, and the papers of Adlai Stevenson and John J. Sparkman, the Democratic presidential and vice presidential candidates.