Steve Carlton holds the all-time strikeout record for lefthanders with 4,136. He is second overall, but still stands a healthy 1,600 behind Nolan Ryan. In a 23-year career with the Cardinals and Phillies, Carlton was good for a 3.22 ERA and led the majors in Ks five times. His 329 wins put him second among lefties, behind only Warren Spahn. Late bloomer Randy Johnson is the next southpaw on the strikeout list with 3,040. Already 37, Johnson would have to pitch until he was 44 (as Carlton did), and average 157 strikeouts per year to overtake Carlton. Though the Big Unit has already led the league in Ks six times, he may find it difficult to maintain those gaudy numbers in the coming years. Carlton averaged only 66 Ks over his last four seasons.
The single-season record for strikeouts by a lefty was set by Sandy Koufax in 1965. That year, his next-to-last in the majors, he fanned an incredible 382 batters while compiling a 26-8 record with a 2.04 ERA. He was the unanimous choice for the Cy Young Award, but was narrowly beaten out by Roberto Clemente for MVP honors. Nolan Ryan beat Koufax’s total by a hair in 1973, when he struck out 383. Randy Johnson is also second among lefthanders on the single-season list. He struck out 364 in 1999.