John Hart is

Juvenile, he is such a child but with really bad language and the ability to flirt with everything like Jack

Obsessed with Jack, I mean who would go through all that trouble to find someone (Not including, Jack, Rose, The Doctor or The Master)

Handsome, what he is, he almost rivals Jack but he is nowhere near as handsome as Ianto

Never seen without his red jacket, it's like Jack and his coat (Love the coat)

His nickname for Ianto is eye candy; this just proves how much he flirts

Adventures, he was once a time agent after all

Reckless, he has nothing but his life to save and he flirts with Ianto while in the same room as Jack

The wife in his and Jacks five year/two week relationship