Tomorrow, Barack Obama is expected to announce that (Boston-born) Peter R. Orszog will be his director of the Office of Management and Budget. This is a cabinet-level position, and, if I'm not mistaken, makes Orszog the first post-Baby Boom Cabinet member.
Interestingly, the current OMB director, Jim Nussle, was the first Cabinet director born in the 1960s, according to my rudimentary research.