Sasudah perang, inyo manjadi sasama di Fermi's Institute for Nuclear Studies. Kamudian inyo bakarajo di Institute for Advanced Study di Princeton, New Jersey, Brookhaven National Laboratory, jo New York University, di mano inyo manjadi profesor pado taun 1962. Panalitiannyo maliputi fisika energi tinggi, astrofisika, jo kosmologi.
Marshall