He served as clerk of the United States District Court of Maine 1917-1920.

He represented Bangor and Eastern Maine in the 3rd Congressional District, taking the seat of his political mentor, Owen Brewster, who had successfully run for the United States Senate.

Fellows began to make a national name for himself in 1948 with 'red-baiting' speeches, such as one in Baltimore in which he said "we need to spray and fumigate the State Dept.

[1] On the other hand, as Chairman of the House Sub-Committee on Immigration, he also sponsored a House bill to admit over 200,000 "displaced persons" (European war refugees) into the United States, and fought as "blatently [sic] discriminatory" the Senate version of the same legislation which would have barred Jews and created preferences for northern Europeans.

[2] Even the Fellows Bill, however, left out Asians, and set a total quota only half as large as the one requested by President Truman.