Minus Mister Roberts the rest of the characters from that classic play have returned to this sequel that presents Ensign Pulver as the leading character. This film makes the assumption that you have seen Mister Roberts so you know who the main characters are and their personalities before you even watch Ensign Pulver.
Playing the roles of Ensign Pulver, Captain Morton, and Doc are Robert Walker, Jr., Burl Ives, and Walter Matthau. Walker is far more a callow youth than Jack Lemmon was in Mister Roberts. After that show of bravado where Pulver through the Captain's prize palm tree overboard, it's once again business as usual with the tyrannical captain going out of his way to be the meanest man on earth running this navy cargo ship, miles away from the action in the Pacific theater.
At first there's a lot more service type comedy than there was in Mister Roberts, but things do take a serious turn when Pulver and the Captain go overboard during a typhoon. Many days on a rubber raft and then on a tropic island make the captain open up and you get some insight why he's the nasty fellow he is.
Some other key roles are Tommy Sands who plays a sailor looking to get leave because his wife just lost their baby and Gerald S. O'Loughlin who gets temporary command of the USS Reluctant when Ives goes missing. In fact Ensign Pulver makes an addition to Mister Roberts in that the ship we see has a full complement of officers other than the four main characters from Mister Roberts. Look for Jack Nicholson in a small role as radioman Dolan and as per the civil rights era, Al Freeman integrates the crew which was not the case in Mister Roberts.
Walker gets a love interest in Millie Perkins an army nurse who sees him for the shiftless character he is and her supervisor is Kay Medford who has a very droll part.
Ensign Pulver is not a classic like Mister Roberts, but it is an amusing service comedy and holds up well today.