The political calculations of the Greek road show have been evident from the itinerary, with early stops in countries seemingly more inclined to lend support. Mr. Varoufakis has visited Paris, where French leaders have been pushing against budget restrictions tied to austerity policies. He also paid a call on Britain, which is not a eurozone member but is a critical center of private investment for Greece. Mr. Varoufakis arrived here on Tuesday to meet with the Italian finance minister, while Mr. Tsipras came to meet with Prime Minister Matteo Renzi.

In a joint news conference Tuesday evening, Mr. Renzi noted that he had some differences with the new Greek leader but that the two men, both 40, represented a new generation. He joked that now it was Mr. Tsipras’s turn to be regarded as a “dangerous man,” much like the criticism that Mr. Renzi faced during his first year in office.

“Alexis’ arrival is a blessing for me,” he said.

The Greek itinerary has prompted many analysts to speculate that the new government is trying to construct a “Mediterranean coalition” against Germany and the European north — a theory that the French and Italians sought to dispel. Finance Minister Michel Sapin of France warned that Greece would not be able to pit his country against Germany, even though the French have expressed support for some Greek positions. Mr. Renzi had also rejected any notion of a coalition of southern countries.

Indeed, the Greek leaders on Tuesday confirmed that they would travel to Brussels and Berlin. Mr. Tsipras is to meet in Brussels with Jean-Claude Juncker, president of the European Commission, on Wednesday before traveling to meet President François Hollande of France. Mr. Varoufakis is to visit Germany on Wednesday and Thursday to meet with Mario Draghi, chief of the European Central Bank, and with Germany’s finance minister, Wolfgang Schäuble.

Mr. Varoufakis has emerged as a provocative, telegenic presence. On matters of substance, he has spoken about European creditors financing a “bridge” agreement to help fund the Greek government while it attempts to renegotiate the terms of its bailout, worth 240 billion euros, or about $276 billion. But it is Mr. Varoufakis’s style that has attracted extra attention. In London, as he arrived to meet with George Osborne, the button-down chancellor of the Exchequer, Mr. Varoufakis wore a leather jacket, an untucked blue shirt and black slacks.