"smiling countenance" is a correct and usable phrase in written English.
It can be used to refer to a person's facial expression which appears to be pleasant or happy. For example: "The children were delighted to see the principal's smiling countenance as she welcomed them into the classroom."
"He certainly speaks well and has a great smiling countenance.
A couple of years ago I bought my mother-in-law a red, white, and blue African-print cloth decorated with the smiling countenance of Barack Obama.
And through it all was the smiling countenance of Muammar el-Qaddafi in his sunglasses and outlandish costumes, hobnobbing with Idi Amin, playing gracious host in Tripoli to visitors seemingly handpicked off Interpol's most-wanted list.
At such moments of truth, we can rely on reassurance only on the face of our stewardess & we have never found comfort in the permanemtly smiling countenance of a trim female who is far too young and far too pretty not to be convinced of her own immortality.
(The living room décor did not help: In each home, there was the same poster featuring the smiling countenances of Mao, Deng Xiaoping and Jiang Zemin, the three paramount leaders of China).
Ninety-two per cent of the Chinese population belong to the ethnic Han majority, and aside from the occasional propagandistic variety show in which ethnic-minority members are paraded on stage in colorful costumes, their smiling countenances signalling solidarity with the government, they have historically been subjected to discrimination and are considered cultural outsiders.
He is seen snapping at his wife, Liza; his assistant, Sona Movsesian; and the "30 Rock" actor Jack McBrayer, whose smiling Southern countenance collapses when Mr. O'Brien serenades him with a piano tune called "You Stupid Hick".
He is described as a pompous man who rarely smiled, although his countenance may have belied a certain generosity [ 55].
Then this ebony bird beguiling my sad fancy into smiling, By the grave and stern decorum of the countenance it wore, 'Though thy crest be shorn and shaven, thou,' I said, 'art sure no craven.
As it emerged in the early hours of Friday that her political backyard of Glasgow was one of the few regions to vote Yes, her smiling demeanour stood in stark contrast to the gloomy countenance of her boss Alex Salmond, who saw his seat of Aberdeenshire vote in favour of the Union.
As he unloaded luggage and pillows from the car, Roethlisberger was smiling and ultrapolite, a departure from the sometimes-distant, sometimes-smirking countenance that used to grate reporters, even telling a cluster to be careful because he did not want to hit anybody with one of his bags.
