Rabbi Joseph B. Soloveitchik, Rosh Yeshiva at Yeshiva University who is frequently referred to simply as “the Rav,” also agreed that Thanksgiving was not a Gentile holiday, and ruled that it was permissible to eat turkey on Thanksgiving.
“Indeed, there were instances when Rabbi Soloveitchik implied to his students that he and his family celebrated Thanksgiving, although shiur was always held on Thanksgiving,” said Rabbi Hershel Schachter in his intellectual biography of Rabbi Soloveitchik, Nefesh HaRav.
According to Dr. Avi Feldblum of Highland Park, NJ, on Thanksgiving day, Rabbi Soloveitchik started his shiur at YU much earlier than usual so that he could be finished in time to catch a plane back to his home in Boston to have a festive meal with his family.
But just because Thanksgiving was sufficiently important for the Rav to start his shiur early, did not mean that he would end it before completing what he wanted to understand. According to Dr. Feldblum, on Thanksgiving 1976, Rabbi Soloveitchik spent about five hours working through one Tosafot. When his aide passed him a note to remind him about his flight back to Boston, the Rav turned to him and said, “No one can leave here until we have understood what it is that Tosafot is saying.”