Candidates for La RÃ©publique en Marche came first in 10 of the 11 seats given to France's 1.3 million expatriates.
Opinion polls at home in France also give Mr Macron's movement a clear lead in elections beginning on Sunday.
Gaining a legislative majority would complete Mr Macron's ground-shaking realignment of French politics.
It would enable him to start work on his programme of reforming the French labour market, reviving the economy and pushing for reform of the European Union.
Currently Mr Macron's La RÃ©publique en Marche (LREM) has no parliamentary seats, and most of his candidates are political novices.
France's expatriates are divided among 11 constituencies created in legislative redistricting in 2010. Their geographical distance means they vote early - but critics have questioned the wisdom of announcing the results so early, saying it could affect the domestic vote.
Just weeks ago, Mr Macron thrust aside rivals from the established centre-left and centre-right parties, to claim the presidency.
His final challenger in the second round was far-right leader Marine Le Pen - leading some to attribute his victory to voters uniting for "anything but Le Pen".
But opinion polls suggest voters are willing to give LREM a chance, despite an investigation into the financial dealings of one of Mr Macron's cabinet ministers.
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The latest Ipsos Sopre-Steria poll on Tuesday putting LREM ahead with 29.5%, projecting that it could end up with 385-415 of the 577 seats in France's lower house of parliament after the second round of voting on 18 June.
The poll placed the centre-right Republicans second with 23%, the far-right National Front third with 17% and the far-left France Unbowed fourth with 12.5%.
The Americas are split into two constituencies, Europe into six, Africa into two, one of which also incorporates many Arab states. The 11th constituency is geographically the largest, spanning other Asian countries, Oceania, Belarus Moldova and Ukraine.
The LREM won many of these seats easily, with support of over 50% - though low turnout of 19.1% means several will be unable to claim the seat before submitting to a second round.
The only constituency not to back an LREM candidate was North-West Africa - though here the leading contender had had her association with LREM withdrawn over questions about her political links.
France's overseas voters have overwhelmingly backed candidates for the nascent party of its new President Emmanuel Macron.