A stronger yen and weaker euro will affect firms' global competitiveness, profits and sentiment, Morimoto said at his first news conference as a board member.
Morimoto, a former executive at Tokyo Electric Power Co (9501.T), Asia's biggest utility, started work on Thursday, filling the final vacancy on the nine-member board.
Due to his lack of experience in monetary policy, Morimoto is thought likely to vote with the majority of the board at least in the near term.
The BOJ's next policy meeting is on July 14-15. (Reporting by Rie Ishiguro; Editing by Chris Gallagher)