Upon its release, the album received generally positive reviews amongst critics. Commercially, it opened at number 23 on the US Billboard 200 and at number 5 on the Top R&B/Hip-Hop Albums with 12,000 copies. It marked Blige's 15th top ten title on the latter chart, tying her with Snoop Dogg for second-most top ten entries in the Nielsen SoundScan era. The album was certified Gold by the RIAA on December 4, 2013, which indicateds sales of over 500,000 copies.
This album is the first collaboration between legendary producer and hit-maker David Foster and Blige. The album will also be released on The Verve Music Group, in which Foster is the chairman of. Foster is also the producer of multi-platinum Christmas albums by Michael Bublé, Rod Stewart, Andrea Bocelli, Josh Groban and Celine Dion.Chris Walden wrote two arrangements for the album.
Andy Kellman of Allmusic rated A Mary Christmas three out of five stars. He felt that the album "won't likely reach the high status of, say, Mariah Carey's Merry Christmas, but it's a full-effort holiday release that many of her fans should be able to enjoy for several years."
A Mary Christmas debuted at number 23 on the US Billboard 200 and at number 5 on the Top R&B/Hip-Hop Albums with first week sales of 12,000 copies. After four weeks of fluctuating on the chart, A Mary Christmas entered the top 20 for the first time in its sixth week, rising from number 22 to number 13 with a 110% sales increase to 31,000 copies. In its seventh week, the album experienced an 82% increase to 57,000 copies sold, despite falling two positions to number 15. In its eight week, the album rose to number 10 despite a 10% drop to 51,000 copies, giving Blige her 12th top ten album.A Mary Christmas rose less than 1% to 52,000 copies sold in its ninth week, falling one spot to number 11. In its tenth week, A Mary Christmas fell to number 13 with a 25% increase to 64,000 copies sold, the album's best-selling week. In its eleventh week, the album sold approximately 32,000 copies (a decline of 49% from the previous week) and placed at number 21 on the Billboard 200, reflecting the end of the 2013 holiday season.A Mary Christmas was the third best-selling Christmas album of 2013 with 328,000 copies sold for the year.
On December 4, 2013, the album was certified Gold by the RIAA.