The 57-year-old made the announcement via a statement posted on Instagram.
"Today, quite rightly, being gay is a reason to celebrate and be proud," he wrote.
"Yes, I am feeling pain and confusion, but that comes only from the hurt that I am causing to my family."
Mr Schofield presents ITV programmes including Dancing On Ice and This Morning, which won a National Television Award last week for best live magazine show.
The presenter was interviewed by his co-host Holly Willoughby on Friday's edition of This Morning.
"You know this has been bothering me for a very long time," he said.
"Everybody does this at their own speed when the time is right."
The presenter added in recent times his sexuality has "become an issue in my head".
"All you can be in your life is honest with yourself and I was getting to the point where I knew I wasn't honest with myself. I was getting to the point where I didn't like myself very much because I wasn't being honest with myself."
"[Coming out] is my decision. This is absolutely my decision. It was something I knew that I had to do. I don't know what the world will be like now. I don't know how this will be taken or what people will think."
But the presenter said he is not ready yet for a relationship with a man.
Phillip Schofield's statement in full:
"You never know what's going on in someone's seemingly perfect life, what issues they are struggling with, or the state of their wellbeing - and so you won't know what has been consuming me for the last few years. With the strength and support of my wife and my daughters, I have been coming to terms with the fact that I am gay.
"This is something that has caused many heart-breaking conversations at home. I have been married to Steph for nearly 27 years, and we have two beautiful grown-up daughters, Molly and Ruby. My family have held me so close - they have tried to cheer me up, to smother me with kindness and love, despite their own confusion. Yet still I can't sleep and there have been some very dark moments.
"My inner conflict contrasts with an outside world that has changed so very much for the better. Today, quite rightly, being gay is a reason to celebrate and be proud. Yes, I am feeling pain and confusion, but that comes only from the hurt that I am causing to my family.