1948 - 1964 If I have my facts straight, it was the Kungsholm for a while - the flagship of the Swedish-American line.

Wikipedia:

For a brief time 1940-41, as Kungsholm was cruising the Caribbean after war broke out in Europe, the author J. D. Salinger was employed aboard as entertainment director

Oh, he must have been a gas.

It spent the war as a troop ship, and then found itself playing out the usual third act: former glory gone, battered from war service, sold to a lesser line. Ie was the Italia for a while, spent a year as the Imperial Bahama, and then it was scrapped in 1965.