Android supported emoji in version 4.1 and above with Android 4.4 KitKat or above required to display color emoji.
Android 7.0 is the first to support Unicode 9 emojis.
Android 4.3 Jelly Bean was the first release to include a built-in keyboard (iWnn IME), and Android 4.4 KitKat was the first to include a color emoji keyboard.
Versions of Android prior to 4.3 require the use of a third-party keyboard app to insert emoji, or can copy/paste emoji from the list of all emoji.
A sample of emoji characters from Android 5.0 Lollipop.
Images via Emojipedia