<P> Over the course of his 17 - year major league career, Lefty Grove led the American League in ERA nine times, with a career single - season low of 2.06 for the 1931 Philadelphia Athletics . Roger Clemens has won the second-most ERA titles, capturing six in the American League and one in the National League . Sandy Koufax led the National League in ERA for five consecutive seasons (1962--1966); Koufax' five awards are the most won consecutively by any player and are tied for the most awards by a player in the National League with Christy Mathewson and Clayton Kershaw . In the American League, Walter Johnson also won five ERA titles, and Pedro Martínez has won a total of five (four American League and one National League) with two different teams . </P> <P> The most recent ERA champions are Corey Kluber in the American League and Clayton Kershaw in the National League . </P> <P> The lowest single - season ERA in league history was posted by Tim Keefe, whose 0.86 ERA in 105 innings pitched for the National League's Troy Trojans in 1880 led his closest competitor by . 52 runs . In the American League, Dutch Leonard's 0.96 ERA is a single - season record . Keefe and Leonard are the only two pitchers ever to allow less than one run per nine innings pitched in a single season . The widest margin of victory for an ERA champion is 1.96 runs, achieved when Martínez' 1.74 ERA led Clemens' 3.70 in the American League during the 2000 season . The largest margin of victory in the National League is 1.26 runs--Dazzy Vance's 2.61 ERA over Carl Hubbell's 3.87 in 1930 . The smallest margin of victory for an ERA champion is . 009 runs . Although the statistic is traditionally recorded to two decimal places by most sources, the 1988 American League title was decided by a margin of less than one hundredth of a run when Allan Anderson's ERA of 2.446 (55 earned runs in ​ 202 ⁄ innings) bested Teddy Higuera's 2.455 mark (62 earned runs in ​ 227 ⁄ innings). Other contests decided by one hundredth or less include Luis Tiant's 1.91 ERA ahead of Gaylord Perry's 1.92 in 1972 and Mark Fidrych (2.34) over Vida Blue (2.35) in 1976 . </P> <Table> <Tr> <Th> Year </Th> <Td> Links to the corresponding "year in baseball" or "Major League Baseball season" article </Td> </Tr> <Tr> <Th> Leader </Th> <Td> Player with the lowest earned run average (ERA) in the league </Td> </Tr> <Tr> <Th> Runner - up </Th> <Td> Player with the second - best ERA in the league </Td> </Tr> <Tr> <Th> League </Th> <Td> Denoted only for players outside of the modern major leagues </Td> </Tr> <Tr> <Th> † </Th> <Td> Member of the National Baseball Hall of Fame and Museum </Td> </Tr> </Table>

Who has the lowest era in mlb history