She attended business school at Columbia University and subsequently worked in the Cabinet Secretariat under Prime Minister Junichiro Koizumi, as a management consultant with Boston Consulting Group, and as a marketing executive for Hermès Japan.

[1] She was first elected to the Diet in the 2012 general election, in which she defeated former Economy Minister (and subsequent Democratic Party of Japan president) Banri Kaieda in the Tokyo 1st district.

[2] Miki was re-elected to serve a further term in parliament in the 2014 general election.

She was appointed (and remains) Vice-minister for foreign affairs in the 3rd cabinet re-shuffle of the Abe administration.

In the 2017 general election, Kaieda defeated Yamada by a small margin in the Tokyo 1st district, but Yamada retained a seat in the Diet through the LDP proportional representation list.