Harper, accompanied by Foreign Affairs Minister John Baird, leaves Friday on a trip that will include a meeting in Kyiv with newly minted Prime Minister Arseniy Yatsenyuk to offer Canadian support to Ukrainians.
The brief trip to Ukraine — Harper will spend just a few hours there after travelling to Kyiv from the Netherlands — comes a few days before the prime minister is expected to make the case for a tough, united G7 front against the Russians.
The G7 nations are holding an emergency meeting on the sidelines of the Nuclear Security Summit in The Hague, taking place on Monday and Tuesday, to discuss the biggest crisis in eastern Europe since the Cold War era.
Harper, one of the most senior of the G7 leaders — comprised of the United States, Britain, Germany, Japan, France, Italy and Canada — holds some sway over his colleagues because of his consistent warnings about Russian President Vladimir Putin, says one foreign policy expert.
Canada's large Ukrainian community of 1.2 million people also lends Canada an air of credibility on the file, said Fen Hampson, a director at the Centre for International Governance Innovation in Waterloo, Ont.
"The Western alliance has been behind the ball and finally, finally countries are waking up to the fact that Putin really means business," Hampson said.
"He's not going to be brought to the negotiating table with rhetoric and speeches full of sound and fury signifying little action. And Harper and the Canadian government have taken a pretty consistent line from the very beginning that this was big trouble brewing, so there is respect there."
Russian troops moved into Ukraine's Crimean Peninsula three weeks ago in a move that was widely condemned as a brazen and illegal territory grab. The Kremlin has since formally annexed the strategically significant region.
Earlier this week, Harper announced Canada was imposing further sanctions on Russia following Sunday's vote in Crimea to secede from Ukraine. The Conservative government placed economic sanctions and travel restrictions on senior officials in Russia and Ukraine, particularly those in Crimea.
For all the symbolic importance of Harper's visit to Ukraine, however, Germany is thought to be the country to watch during the prime minister's European trip. Harper will visit German Chancellor Angela Merkel late next week.
Germany is one of the G7 countries that's advocated a more cautious approach rather than playing economic hardball with the Russians.
That's largely because of Germany's economic ties to Russia, including a dependence on Russian oil and gas, and a post-Second World War foreign policy mandate called Ostpolitik that's aimed at maintaining positive relations with Russia, said Roland Paris, director of international policy studies at the University of Ottawa.
"Ostpolitik is an established foreign policy doctrine in Germany that is concerned with managing relations with Russia and avoiding a rupture in those relations, so there are a lot of pressures on Angela Merkel not to take strong economic action against Russia," he said.
"I don't think it's a coincidence that the prime minister has chosen to meet with Merkel as part of this trip. To the extent that he can reinforce to the German leader the importance of a very strong and united stand against Russian intervention, Canada could play a small but useful role here."
German industry and public opinion polls have suggested a majority of Germans are opposed to full-scale economic sanctions against Russia.
Merkel, however, was reportedly stung by Putin's false assurances to her that he would not take military action in Crimea — a state of indignation that could make her more receptive to Harper's calls for more severe economic sanctions.
Harper can also point to Canadian energy exports as an alternative to Russia's old and gas, Hampson noted.
The prime minister and the German chancellor, the two most senior members of the G7, have a close relationship, Hampson added, recalling Merkel's visit to Canada in August 2012 when the pair went to Harrington Lake and "talked late into the night."
"There is clearly both a deep personal respect and a mutual affection between these two very senior leaders. If anyone can convince Merkel to take a harder stance against the Russians, it's our prime minister."
Follow Lee-Anne Goodman on Twitter at @leeanne25