The first well known pitcher in MLB history to throw more than one no hitter was Cy Young, who threw his first on 9/18/1897, pitching in the National League for the Cleveland Spiders. However, he was not the first to throw two, or even three. He would throw two more: on 5/5/1904 and 6/30/1908, both pitching for the early Boston franchise of the American League. Christi Mathewson of the New York Giants was next, throwing his two in 7/15/1901 and 6/13/1905. White Sox RHP Frank Smith, a known spitballer, threw his two no hitters on 9/6/1905 and 9/20/1908. Next would be the positive part of what would be a sad story, and that was Cleveland's RHP Addie Joss. Within a year of his second no hitter, he was dead of typhoid fever. Joss threw his two no hitters on 10/2/1908 and 4/20/1910.
Dutch Leonard was one of a series of talented pitchers the early Red Sox teams had. He threw his two on 8/30/1916 and 6/3/1918; both years the Red Sox would win the World Series. It would be nearly 20 years until a pitcher would throw his second career no hitter. It would happen in historic fashion. The legendary Vander Meer would throw his back to back no hitters for the Cincinnati Reds on 6/11 and 6/15/1938; something that has never been matched.
In the history of MLB, there have been five pitchers (including Vander Meer) who have thrown two no hitters in the same season. After Vander Meer, the next was Allie Reynolds of the Yankees, who threw his two on 7/12 and 9/28/1951. The next year, the same feat was accomplished by Detroit's Virgil Trucks, who threw his on 5/5 and 8/25/1952. Nolan Ryan threw two no hitters for the California Angels in 1973 (5/15 and 7/15) and Roy Halliday threw his two for the Phillies in 2010 (on 5/29 and in the postseason on 10/6).
Next is the pitchers who pitched two no hitters, but combined with relievers to finish one of them. Of course, the rules changed over the past ten years, making an official no hitter being 9 complete innings of no hit baseball. Many pitchers previously credited with no hitters had theirs taken out of the record books. The first pitcher who threw a no hitter with some help was Athletics LHP Vida Blue on 9/21/1970. He pitched 5 innings and with the help of 3 relievers gave up no hits. A little over 5 years later, on 9/28/1975, Blue finished his own no hitter, giving him credit for 2 in his career. The same happened for Kent Mercker of the Atlanta Braves. His first no hitter was on 9/11/1991, when he combined with 2 relievers after pitching 6 no hit innings. On 4/8/1994, he did it himself, throwing the 2nd one of his career. Kevin Millwood threw a no hitter for the Phillies on 4/27/2003. Just last season, while pitching for the Seattle Mariners, he combined with 4 relievers to throw a no hitter on 6/8/2012.
Then there are the pitchers who threw no hitters for two different teams. Cy Young was the first to do that, throwing one for the Cleveland Spiders of the National League and two for the Boston team of the American League. Ryan, of course, threw no hitters for 3 different teams. Millwood threw his two pitching for two different teams. Hideo Nomo threw his first one for the Los Angeles Dodgers on 9/17/1996 and his second for the Boston Red Sox on 4/4/2001. Randy Johnson threw his first for the Seattle Mariners on 6/2/1990, then his perfect game for the Arizona Diamondbacks on 5/18/2004. Jim Bunning threw his first on 7/20/1958 pitching for the Detroit Tigers, then his second (also a perfect game) came for the Phillies on 6/21/1964.
And now on to those who have thrown more than two. We all know about Ryan and his seven (5/15/73, 7/15/73, 9/28/74, 5/1/75, 9/26/81, 6/11/90, 5/1/91). I mentioned Young's three (9/18/1897, 5/5/1904, 6/30/08). It is amazing that I have spoken about no hitters and not mentioned Sandy Koufax, who threw four: on 6/30/62, 5/11/63, 6/4/64 and 9/9/65. He is the only pitcher in MLB history to throw a no hitter in four consecutive seasons. Larry Corcoran pitched for the Chicago National League club in the 1800s and threw three (8/19/1880, 9/20/1882 and 6/27/1884). Corcoran became the first MLB pitcher to throw two, then three no hitters. Bob Feller threw his three for the Indians on 4/16/40, 4/30/46 and 7/1/51.
Interestingly enough while touching on pitchers who pitched no hitters for more than one team, there is the other aspect in regards to those who have pitched one in both the American and National Leagues. Young was the first to do that, and has been joined by Randy Johnson, Hideo Nomo, Kevin Millwood and Jim Bunning.
Those who have pitched more than one no hitter, that I have not mentioned, include Hall of Famers Warren Spahn (Milwaukee Braves 9/16/60, 4/28/61) and Pud Galvin (Buffalo Bisons 8/20/1880, 8/4/1884). Others include Carl Erskine of Brooklyn on 6/19/1952 amd 5/12/1956, the Cubs Ken Holtzman on 8/19/69 and 6/3/1971, Bill Stoneman of the Montreal Expos on 4/17/69 and 10/2/72, Don Wilson of the Houston Astros on 6/18/67 and 5/1/69, Steve Busby of the Kansas City Royals on 4/27/73 and 6/19/74 and Bob Forsch of the Cardinals on 4/16/78 and 9/26/83. Oddly enough pitchers with the same names, Sam Jones threw no hitters. "Sad" Sam Jones threw one for the New York Yankees on 9/4/22 and Sam "Toothpick" Jones pitched one for the Chicago Cubs on 5/12/1955. In the history of major league baseball, only the San Diego Padres remain as the only team to not have a no hitter thrown for them.