September 15, 1979
Bob Watson, a career journey man and two-time All Star for the Houston Astros became the first Major League Baseball player to hit for the cycle in both the National League and American League on September 15th, 1979.
With Houston, Watson hit for the cycle on June 24, 1977. He went 4-4 and drove in 5 RBIs, which is fairly impressive considering it was accomplished while wearing those hideous Astros rainbow jerseys. Nevertheless, two years later on September 15, 1979, Watson hit for the cycle again and went 4-5 with the Boston Red Sox.
Impress your co-workers: Since Watson, John Olerud has duplicated the feat of hitting for the cycle in both the AL and NL; with the NY Mets on September 11, 1997 and with the Seattle Mariners on June 16, 2001.