The song came off the band's major label debut, 1988's Nothing's Shocking. [Note that "Jane Says" from the same LP was featured on ERV in January 2014.] The album created a stir in the music industry, but did not become a huge commercial success. In retrospect, album sales were hurt by the lack of exposure on MTV, and by the diverse alternative feel that the record had -- remember that 1988 was the peak of hair metal.
On the exposure front, the (edited) video below was shot in 1988 at Scream (an alternative rock club in LA), and is an awesome Jane's Addiction timepiece. The vid was banned by MTV for years, due to the nudity and general weirdness (I believe that MTV dropped the ban in 1990).
Sadly, "Mountain Song" did not chart, while the Nothing's Shocking LP only reached #103 on the album charts.
For more on Jane's Addiction (including the story behind Jane), check out the "Jane Says" entry.