In 1910, he made an unsuccessful run for the Senate.
Later, he was elected as a Democrat to the Senate in 1913 to fill the vacancy caused by the death of George S. Nixon, and served until his own death in 1940.

Between 1933 and 1940, during the Presidency of Franklin D. Roosevelt, Pittman was the chairman of the powerful Committee on Foreign Relations and a member of the Committee on Territories and the Committee on Industrial Expositions.
In addition, during those years Pittman was also President pro tempore of the United States Senate.

Among his legislation is the Pittman–Robertson Wildlife Restoration Act of 1937 which set up a formula for federal sharing of ammunition tax revenue for establishing state wildlife areas.
 The program is still in effect.
The Key Pittman Wildlife Management Area near Hiko, Nevada, which encompasses the Frenchy and Nesbitt Lakes, is named in his honor.
In 1910, he made an unsuccessful run for the Senate. Later, he was elected as a Democrat to the Senate in 1913 to fill the vacancy caused by the death of George S. Nixon, and served until his own death in 1940.
Between 1933 and 1940, during the Presidency of Franklin D. Roosevelt, Pittman was the chairman of the powerful Committee on Foreign Relations and a member of the Committee on Territories and the Committee on Industrial Expositions. In addition, during those years Pittman was also President pro tempore of the United States Senate.
Among his legislation is the Pittman–Robertson Wildlife Restoration Act of 1937 which set up a formula for federal sharing of ammunition tax revenue for establishing state wildlife areas.  The program is still in effect. The Key Pittman Wildlife Management Area near Hiko, Nevada, which encompasses the Frenchy and Nesbitt Lakes, is named in his honor.
Key Pittman