Since he came here this fall, jockey Jack Kaenel hasn't gone Hollywood -- no gold chains, sunglasses or shirts open to the navel. He still wears the cowboy hat that became famous when he won the 1982 Preakness. He's still the one-of-a-kind Cowboy Jack.

Even so, the race track people who knew Kaenel when he was riding in Maryland wouldn't completely recognize him now. A year ago he was widely regarded as an immature kid who was wrecking his career with his own irresponsibility. Almost overnight he has become serious and motivated to succeed against the toughest riding competition in the United States.

At the time of his Preakness victory aboard Aloma's Ruler, it was hard to think of Kaenel as a mere child because he was so self-confident, so skilled as a rider, so experienced. Having spent his life around the midwestern bush tracks where his father trained cheap horses, he had ridden his first race when he was 11 and dropped out of school in ninth grade to work at the track full-time. When he came to Maryland, he falsified his age on his license application and started riding in the major leagues at 15.

But, for all of his precocity, he was still a kid with a wild streak that exasperated the trainers he worked for. Frequently Kaenel's agent would commit him to ride horses, but the jockey wouldn't show up. "On days when I didn't feel like riding," Kaenel admitted, "I'd say the heck with it and take some time off to go hunting or fishing."

Kaenel already had alienated a number of clients when he pulled his ultimate disappearing act last spring. Even his agent didn't know where the jockey had gone when Kaenel turned up riding in Chicago. ("I went out there to visit my mom and sister and just wound up staying . . . ")

Kaenel acknowledges that his success in Maryland came almost too easily for him. But even when he was goofing off, he was harboring grander ambitions. He wanted to ride in California, where the best jockey colony in America includes names such as Laffit Pincay Jr., Chris McCarron, Bill Shoemaker and Sandy Hawley. "I'd had the idea for a couple of years, but the situation never came up right," Kaenel said. "This year it finally did."

Kaenel got an agent, Vic Lipton, who was well-connected at the southern California tracks. He also got married (in the winner's circle at a track in Omaha) and he felt that he was ready to settle down a bit.

So when he came to California, he went to work. "I go to the track every morning, go to the barns, see trainers, try to break in that way. I know I've got to hustle. I'm taking care of myself -- I feel better, physically and mentally, than I ever have." And, needless to say, Kaenel is not disappearing to go hunting or fishing.

Kaenel was the eighth-ranked rider at Santa Anita in the fall. At the current Hollywood Park meeting, he has been somewhat less successful, with only six victories in 98 mounts, but he is realistic enough to know that success won't come easily at this level of competition. He is sufficiently encouraged by his performance that he is looking for a house to buy here ("I've never said that before") and he hopes he some day will be one of the top jockeys here, in the class of McCarron and Pincay.

"That's what I'm shooting for," Kaenel said, "and I'm going to keep on working for it. If I don't make any mistakes, I think I can get there."

His ambition is a lofty one, but Kaenel has a long time in which to achieve it. It is hard to believe, but he still is only 20 years old. It is even hard for the jockey to believe. "Doesn't it seem," he asked, "that I've been around for a long time?"