David Ellison will soon take over as the entertainment giant’s CEO — but his mogul father, Larry, put in the $6 billion to buy it.

Larry Ellison, left, whose estimated net worth of $155 billion makes him one of the world’s richest people, is backing an $8 billion bid by his son, David, at right, to take over Paramount.

For decades, Larry Ellison reveled in being the Silicon Valley executive who really knew how to have a good time. He spent as much as $200 million building a Japanese-inspired imperial villa near ...