The guilty man, who has been in custody for two years, is expected to appeal.
The trouble broke out at about 9pm on 5 April 2000 near Taksim Square. Leeds fans had arrived in the hours before to be greeted by banners which said: "Welcome to Hell".
In the melèe Galatasaray supporters and Leeds fans struck each other with fists, feet, chairs and bottles. Pub landlord Mr Speight, 40, was reportedly attacked by a large group of men armed with machetes and knives.
He was taken to the German Hospital but the father of two died later that night. Fibre-optics engineer Mr Loftus, 37 and single, was also killed in the clashes. Four other Leeds fans were injured, one seriously.