Hart spoke to Southgate before joining West Ham and they agreed that it would be best if he played in the Premier League this season.
"I kept him updated with my situation," Hart told the Daily Mail. "Gareth thinks West Ham is the right place for me to be. I want to play at the highest standard available to me. This definitely fits this criteria.
"I've always said the standard of keepers in England is very high. Big Fras [Fraser Forster] has signed a new deal at Southampton. Heaton has been nothing short of a miracle for Burnley with his performances.
"It is tough to get into a Premier League team, I found that out myself this summer."