We know that Dick Whitman was born in 1926 in Illinois, the son of a prostitute who died in childbirth. During the Korean War, Whitman reinvented himself as Don Draper, his commander who was killed in an accident caused by Whitman. The Draper identity was an opportunity for Dick to remake himself, escaping his poverty-stricken and unhappy childhood.
Mad Men makes much of Whitman/Draper's dual identity, and one of the major hinge moments of the show was Whitman/Draper's eventual divorce, caused in large part because his wife discovered his true identity.
However, a gaping hole in the story is Dick Whitman's baseball past. Prior to Korea, Whitman had made it as a Major League baseball player, playing a handful of seasons with the famed post-war Brooklyn Dodgers and the forgettable post-war Phillies.
In all seriousness, the real Dick Whitman's chronology almost fits the fictional characters. The baseball player was born in 1920, only a few years ahead of the fictional character. Whitman was born in Oregon, yet found himself on the East Coast and like the character, is easily imagined as a rural ingenue struggling to find his place on the big stage.
The 1946 Dodgers were a very good team, winning 96 games (on the old 154 schedule) and finishing second in the National League. The Dodgers were in first place through late August, then fell into second, before making a late surge to move back into first in the last week of the season. They finished tied with the Cardinals, playing the first ever playoff series to decide the pennant.
A utility outfielder on that team, Whitman would be indirectly replaced the next season by some player known as Jackie Robinson.