DiMaggio was one of the leading performers, if not the leading performer of the incredible 1941 season. The Yankees won the AL pennant and went on to defeat the Brooklyn Dodgers in the World Series four games to one. (Within ten years Brooklyn would replace the New York Giants as National League archrival to the Yankees, before both NL teams decamped to the West Coast in 1958.) DiMaggio hit .357 in 1941 with 30 home runs and a league-leading 125 RBIs. He again led the league in total bases and was second in slugging percentage and runs scored, but he did not win the league batting title. That honor went to DiMaggio's hitting rival, Ted Williams, who that season hit .406—that last man in major league baseball to bat over .400 for an entire season. DiMaggio, however led his team to the pennant and for that, and other exploits on the field he won his second MVP award.
The other exploits during the 1941 season included what is known simply as The Streak, which many baseball experts and fans consider the one baseball mark that will never be surpassed. Beginning on May 15th and continuing until July 16th DiMaggio hit safely in 56 consecutive games. Against the Boston Red Sox (Williams's team) on July 2nd, DiMaggio hit a home run to break Wee Willie Keeler's record; it was the 45th consecutive game in which he got a least a hit. The streak was finally halted two weeks later in Cleveland by Indians pitchers Al Smith and Jim Bagby and two outstanding defensive plays by third baseman Ken Keltner. DiMaggio then hit safely in 16 consecutive games beginning with the game after the streak ended. In that run he hit in 72 out of 73 games. The only sad note for the Yankees during the streak was Lou Gehrig's death from ALS on June 2nd. When the season was over the Associated Press named DiMaggio as Athlete of the Year. To top off his year, Joe DiMaggio, III was born on October 23, 1941.
The 1942 season was DiMaggio's last for the Yankees for a long time. His offensive numbers were down from the previous few years, but only slightly—he still finished in the top ten or even the top five in most important hitting categories—and the powerful Yankees again won the AL pennant, though were defeated by the St. Louis Cardinals in the World Series. But in 1942 war, which had been raging in Europe and Asia for years, finally embroiled the United States. Like many ballplayers of the era, DiMaggio volunteered for the military, though grudgingly. A few, such as Williams, actually saw combat action, but most were ensconced on military bases playing exhibition baseball games to lift the morale of the servicemen. DiMaggio, who enlisted in 1943 and held the rank of sergeant in the Army Air Corps, fell into the latter category. During these years the DiMaggios' shaky marriage fell apart. They were divorced in May 1944. Dorothy Arnold was granted custody of their two-and-a-half-year old son, and thereafter the extremely private DiMaggio's relationship with Joe III was strained, even into adulthood.