He designed, among other things, the redevelopment of the interior of Trondhjems Sparebank from 1921 to 1924, which later won the Houen Foundation's prize in 1927.

[1] Holmgren was educated at Norwegian Institute of Technology in 1903.

He was hired soon after by Lars Solberg in Trondheim as an assistant architect.

From 1904-1907, he worked on many buildings in Ålesund to help rebuild after the great city fire there.

He designed a number of tenements in Trondheim that were built in the style of Neoclassical architecture.