Raich stood fifth after the first run, but his second effort of 1 minute, 18.05 seconds was 0.22 of a second faster than anybody else.
He had a combined time of 2:35.00 with France's Joel Chenal second in 2:35.07. Hermann Maier of Austria was third in 2:35.16. Francois Bourque, who led Chenal by 0.19 seconds after the first run, managed only the 12th fastest time in the second trip down the hill and slipped to fourth.
American Bode Miller, without a medal in the Turin Games, tied for sixth after completing the first run in 12th place. Miller's last hope for a medal will come Saturday in the slalom.
Raich leads the overall World Cup race after finishing second to Miller in 2005. Raich was third in the World Cup standings in 2004, but until Monday had never won an Olympic gold. He claimed a bronze in the both the slalom and alpine combined at Salt Lake City four years ago.