Carlson graduated from the University of Colorado in 1902 and earned his law degree there in 1904. He practiced law in Fort Collins, Colorado, from 1905 to 1908, and was district attorney in Fort Collins from 1908 to 1914. He ran for governor as a Republican in 1914 and won, benefiting from vote-splitting between Democrats and Progressives.
Carlson's administration was noted for labor reforms, including the passage of a workers' compensation law and the establishment of the Industrial Commission of Colorado. He also supported and signed into law a prohibition bill making Colorado a "dry state."
Carlson was defeated for reelection in 1916. After leaving office, he returned to law practice in Denver.