Magath arrived at Craven Cottage as a replacement for Rene Meulensteen in February, with the club rock bottom of the Premier League table.
Fulham failed to climb away from danger in the remaining 12 games, ending the campaign 19th, four points adrift of safety with the worst goal difference in the league.
Hangeland, who spent six and a half years at the club after joining from Copenhagen, left Craven Cottage at the end of 2013-14 and has voiced his criticism of Magath and his methods.
"He's very difficult to work with," the Norwegian told Sky Sports News.
"He's a very strict manager and his main tool is to try to mentally and physically batter his players and hopefully get some results out of that.
"Is that the right fit for English football? I don't think so. I thought rather than help us try to avoid relegation he made things worse.
"I hope I'm wrong but I don't think he is the right man [to get Fulham promoted] and things will get worse before they get better."
Hangeland also expressed his disappointment at the way his departure from the club was handled.
"With the right signs and the right players coming in I would have been prepared to stay," he said.
"There was a release clause in my contract which they decided to take. I would have hoped for at least [to have been told] face to face or a pat on the back after six and a half years."
