If you've formed the impression from TV that he's a bit of a pit bull, remember there's a softer, more generous man inside.
Sir Alan Sugar's boardroom is the last place the five remaining contestants vying for a top job at his company on BBC2's cut-throat reality TV show The Apprentice would expect to find a charitable soul.
The man ranked 71st in last weekend's new Sunday Times Rich List with an estimated £790m fortune recently complained about his television persona, saying: "You don't get to see any of the light-hearted, friendly side because, as far as the TV producers are concerned, that doesn't put bums on seats."
Despite his ferocious temper and obstinate manner, Sugar is heavily involved in charity work. The Alan Sugar Foundation has reportedly donated more than £3m to charity since it was founded in 1986.
"We're an enabling charity supporting a number of good causes working in fields as diverse as education and the elderly," explains a spokesman.
"But Sir Alan is very private about who the foundation supports."
Sugar isn't so private about his backing for Great Ormond Street Hospital.
The entrepreneurial role model gave his fee for the second series of The Apprentice and royalties from the accompanying book to the charity, and even engineered a task in which his subordinates were instructed to create and design a calendar to raise money for the hospital.
He also donated to GOSH his fee from a series of recent National Savings & Investment TV adverts and his winnings from the Christmas special of Who Wants To Be A Millionaire?.
"I want to avoid people saying 'What's he doing that for? Hasn't he got enough money?'" says Sugar. "I really hate that feeling."