After the war, he was employed in lumber woods and as an iron ore miner and also as a law clerk at Wakefield, Michigan, 1919–1924.

In 1948, he made an unsuccessful bid to be elected the United States Senate, losing to Republican Homer Ferguson.

He also proposed a bill to establish the Isle Royale National Park, located in Lake Superior and had the honor of dedicating it in August 1946.

In 1940, Hook alleged in Congress that Martin Dies had ties to William Dudley Pelley, the leader of a fascist organization, the Silver Legion of America.

[1] Hook's moniker "Fightin' Frank," earned from high school days, was reinforced once again during an infamous bout on the floor of Congress.

His nemesis, John Rankin of Mississippi, drew his ire, but could not cull a punch, as Hook was later quoted, "A gentleman cannot strike an old man."

The wrassling match was physically initiated by Rankin jumping on Hook's back on Washington's birthday in 1945, during the session.