I don't recall hearing O Holy Night in my childhood, though I'm sure I did. In the early 1960s, as I recall, a young singer from Limerick, Ireland, named Tommy Drennan recorded it and it became a big hit in my country. I was in the seminary then.
There are many recordings of this song. Some are quite wonderful while some are not. Peruvian tenor Juan Diego Flórez sing in the original French, by Placide Cappeau, and in the English version by John Sullivan Dwight that most of us are familiar with. You can find the words of both versions here. Adolphe Adam set Cappeau's poem to music in 1847. Cappeau had written the poem at the request of his parish priest but some years later the Church in France banned the use of the song for a while. You can read about it here. (That page gives the surname of the composer as 'Adams' but elsewhere he is 'Adam'.)
I have always liked the version of American soprano Leontyne Price best. She recorded it with the Vienna Philharmonic Orchestra conducted by Herbert von Karajan. He was born in Salzburg, Austria, where Mozart was also born, and the most beautiful city I have ever visited. I was there for a few days in the spring of 1988. (Silent Night originated in the village of Arnsdorf, in the province of Salzburg of which the city of that name is the capital.)
The video of Juan Diego Flórez was made at a Christmas concert in Vienna in 2008 while the recording of Leontyne Price was made in 1961. I have always found it difficult to make a final choice of favourites of anything. I hope you enjoy the glorious tenor voice from Lima, Peru, and the sublime soprano voice from Laurel, Mississippi, USA.