Well, no. It wouldn't be the first kanji of English. Kanji is the Japanese pronunciation of 漢字 (hanzi), where 漢 means han/China and 字 means character/letter. Ergo, it makes no sense to call it "the English language's first and only Chinese character."
If you need to use a Japanese word to describe this, then 絵文字 (e mo ji; picture, character/symbol) fits better, but we already have several words for that, like pictogram or pictograph. One could argue that smileys fall into this category as well. So perhaps it's a smiley.