Hamlet complains of the drunken carousing at Elsinore to his friend Horatio, who asks “Is it a custom?” Hamlet replies that it is and adds, “but to my mind,—though I am native here and to the manner born,—it is a custom more honour’d in the breach than the observance.”
“As if to the manner born” is used to praise someone’s skill: “Reginald drives the Maserati as if to the manner born” (as if he were born with that skill).
“To the Manor Born” was the punning title of a popular BBC comedy, which greatly increased the number of people who mistakenly supposed the original expression had something to do with being born on a manor. Perhaps because of the poetically inverted word order in “manner born” the expression tends to occur in rather snooty contexts. Nevertheless, the correct expression is “to the manner born.”