William Salmon taught in public and private schools for six years and also engaged in agricultural pursuits. He served as special circuit judge of the eleventh judicial circuit of Tennessee in 1908. He was president of the Columbia Board of Education from 1908 to 1922. He commanded an Artillery battery during World War I. He was elected as a Democrat to the Sixty-eighth Congress, serving from March 4, 1923 to March 3, 1925. He was interred in Rose Hill Cemetery in Columbia, Tennessee.