Still popular in his homeland, Katayama has since dabbled in sportscars and GT racing, as well as his other love of mountaineering. One of his most notable performance post F1 was at the 1999 24 Hours of Le Mans, when during the last hour, as he was lapping traffic and closing up the leading BMW in his Toyota GT-One, sharing with compatriots Keiichi Tsuchiya and Toshio Suzuki, his car suffered a tyre blowout and, while he managed to keep the car on the track, he was forced to slowly make his way around the track to return to the pits for a new set. In the process the GT-One lost the chance to contend with the lead BMW, and thus lost the race. The lone GT-One would come home 2nd overall. As a consolation prize, the GT-One would win the GTP class, although it was the only car in the class to actually finish.