In 1906, he designed the Edwin H. Hewitt House in the Stevens Square neighborhood of Minneapolis, listed on the National Register of Historic Places in 1978.

He was married in 1900 and went at once to Paris, where he entered the École nationale supérieure des Beaux-Arts in May, 1901 where he became a member of the Atelier Pascal.

Arriving in Minneapolis, he was almost immediately offered a commission and at once started in on private practice, not having an opportunity to return to Paris for over eight years.

Hewitt resumed private practice, but as business declined during the Great Depression, he closed his office and became the chief architectural supervisor for the Federal Housing Administration for the Minneapolis area.

Alone or in association with Brown, Hewitt was responsible for the design of a number of buildings which have been listed on the United States National Register of Historic Places.