Most of the actors playing disabled people in the film are actually disabled.
The swimming pool that Kenneth Branagh and the actors who play the Warm Springs patients swim in is the actual pool that Franklin Delano Roosevelt and the real patients swam in, and the water is the same mineral water that was used in the pool. The pool was especially refurbished for the film.
Throughout the film Louis Howe (played by David Paymer) is seen wearing an old brown overcoat. The real Louis Howe was known to wear the same clothes again and again, much to the dismay of Eleanor Roosevelt.