Jack Bristow is generally known on Alias as Sydney's cold father. He was married to Irina Derevko, whom he knew as Laura Bristow, not knowing that she was in truth an agent for the KBG. Although it is never stated specifically, it can be inferred (OMG I sound like my English teacher) that Laura's betrayal was what made Jack so cut off, and so hard.

So maybe hard is an understatement. I mean, Jack is scary! The first thing he did when he saw Vaughn was slam him up against the wall! And tells him that Sydney's reason for living is not "those meetings she has with you," but her reason is "taking down SD-6." I hate that conversation, I nearly cry every time I read the transcripts for the episode. I seriously hope that's changed.

Anyway, Jack, despite his cold-ness, has always cared for Sydney. He has always covered for Sydney, protecting her from Sloane or any other aspects in her life. Of course, I'm not exactly one to feel bad for Jack, he scared me, but he's had some hard bits in his life. Most of which because of Irina.

Feel free to add more to this!!

ugh i just died for him when irina betrayed him AGAIN