The next summer, the Royals promoted Wilson to Waterloo, where he won Most Valuable Player and Prospect of the Year awards after leading the league in both hits and steals. He also led in outfield assists.

Willie spent 1976 at Jacksonville in the Southern League, with a short Kansas City call up. 1977 was mostly at Omaha, in the American Association, with another Kansas City appearance. In '78 he reached the big leagues for good. Over the next dozen years Wilson was the lead-off hitter for the Royals helping lead them to the World Series title in 1985. His best season was 1980 – 133 runs scored and 230 hits, with a .326 batting average. Two years later he won the American League batting title with a .332 average.

Willie finished up his career with the Oakland A's and the Chicago Cubs and retired in 1994.

Year after year he was among the league leaders in steals and triples.

After retiring, Willie coached in the Toronto system before joining the private sector in 1997.