They seem to have gotten along reasonably well, especially when you compare them to the relationship between Bismarck and most of the other generals.

However, there were some conflicts between them, the greatest was about the primate of politics over military; Moltke (and the rest of the staff) came to believe that politics would only hinder the generals, and resented the political interventions of Bismarck (B. tried to delay the invasion of Jutland for political reasons) and the leniency B. had shown. Roon for example wrote that the Army would "not just be a scalpel for the diplomats to wield".

This conflict grew in the German war, when the generals wanted to pursue the Austrians, believing "the whole thing could be over in 8 days" when done so. B. convinced the King not to pursue to let the French broker the peace, which would have been hard if the conflict had not been limited in that manner.

Finally, in the Franco-German war, the generals got the King to exclude B. from the war concil. Which was very insulting to B., as he had to get the informations about the meetings from the press, sometimes as long as five days after the meetings. This showed B. quite clearly that he wasn't as indispensible as everyone thought he was. But being Bismarck, he regained the ear of the King, but had to accept the annexation of Elsaß-Lothringen (which was a demand from the staff, Bismarck at one time even considered returning Louis Napoleon to the throne, which would have been hard to do with annexations; Moltke was outraged about this). After the war, they sometimes clashed about politics; for example Moltke was against the Kaiser-Wilhelm-Kanal.

This all seems quite like dislike, right? But in his memoirs, Bismarck does not say one little bad word about Moltke (one has to consider that Moltke was a god-like-figure to the Prussians by 1890; when a (labourer) newspaper asked in 1899, who the most important scientist of the 19. century was, the reader voted Moltke first place before Darwin). B.'s memoirs are known to be not very objective.

He even heaps all the blame for the war council on the "demigods" (quote from the memoirs) in the staff, meaning everyone but Roon and Moltke. There are some anecdodes in the memoirs about Moltke as well, like that Bismarck privately sometimes dinned with M (namely the day after B. resigned).

And one that I like: (it does not translate very well, I am afraid) Moltke was known to be silent and stoic. When the war against Austria and the rest of the German states broke, Moltke (among others) visited B., and after the discussion, when he stood in the doorway, M. again turned to B. and said "Wissen Sie, dass die Sachsen die Elbbrücke gesprengt haben?" "Do you know that the Saxons have blown up the Elbe-bridge?" - "Haben sie?" "Have they.", a surprised Bismarck asks. A smiling Moltke answered: "Ja, mit Wasser" "Yes, with water".

The joke is that in German, sprengen also can mean "to sprinkle with water", like to water the lawn, "den Rasen sprengen" , not only to blow up.