[1] When McColloch was two years old, the family relocated to Oregon, where he received his education through high school in Portland.
[1] He graduated from law school in 1909, with a Bachelor of Philosophy degree and was admitted to the Oregon bar in May of that year.
[2] McColloch remained in Baker until 1913, and served in the Oregon State Senate after winning election to a four-year term in 1910.
[2] In 1926, McColloch moved to Southern Oregon where he set up private practice in Klamath Falls.
[2] On August 5, 1937, President Franklin D. Roosevelt nominated McColloch for a position on the United States District Court for the District of Oregon to replace the deceased Judge John Hugh McNary.