[1] He served as Postmaster General for most of the administration of President Andrew Jackson and was the only Cabinet member not to resign in 1831 as a result of the Petticoat affair.

During his time in the Kentucky Senate Barry wrote to former President James Madison seeking support for a plan of subsidizing public education across the state; Madison responded enthusiastically and included in his letter of August 4, 1822 the often-cited observation: "A popular Government, without popular information or the means of acquiring it, is but a Prologue to a Farce or a Tragedy; or, perhaps both.

[4] He was the only member of Jackson's original Cabinet not to resign as a result of the Petticoat Affair, which involved the social ostracism of Margaret O'Neill Eaton, the wife of Secretary of War John H. Eaton by a coalition of Cabinet members wives led by Second Lady Floride Calhoun.

[5] He was appointed ambassador to Spain, but died before he could take office en route to his post, while stopped in Liverpool, England August 30, 1835.

During the 1820s, Barry was a member of the prestigious society, Columbian Institute for the Promotion of Arts and Sciences, who counted among their members former presidents Andrew Jackson and John Quincy Adams and many prominent men of the day, including well-known representatives of the military, government service, medical, and other professions.