He attended the common schools and the high school of Eaton Rapids, and apprenticed to the printing business from 1891 to 1899. Woodruff graduated from the dental department of the Detroit College of Medicine in 1902 and practiced dentistry in Bay City from 1902 to 1911.
He enlisted as a corporal in Company G, Thirty-third Regiment, Michigan Volunteer Infantry, during the Spanish–American War. He saw active service and was mustered out. He was mayor of Bay City from 1911 to 1913.
In 1912, Woodruff defeated incumbent Republican United States. Representative George A. Loud to be elected as the candidate of the Progressive Party from Michigan"s 10th congressional district to the 63rd Congress, serving from March 4, 1913 to March 3, 1915.
Woodruff and William J. MacDonald (12th district) were the only two Michiganders elected to the United States. House from the Progressive Party. He was not a candidate for re-nomination in 1914 and served for two years in the First World War as an Infantry officer, acquiring the rank of major during his service in France.
In 1920, Woodruff returned to Congress, elected as a Republican from the same district to the 67th Congress. He was subsequently re-elected to the fifteen succeeding Congresses, serving from March 4, 1921 to January 3, 1953.
He was re-elected unopposed in 1922 and 1926 and was alternate delegate to Republican National Convention from Michigan in 1940.
He was not a candidate for re-nomination in 1952 to the 83rd Congress. He died in Washington, District of Columbia a little over a month after leaving office and a month before his seventy-seventh birthday. He is interred in Elm Lawn Cemetery of Bay City.