He was graduated from the law department of the University of Missouri in March 1879.

He was admitted to the bar in 1879 and commenced practice in Perryville.

Robb was elected prosecuting attorney of Perry County in 1880 and reelected in 1882.

He was an unsuccessful candidate for reelection in 1904 to the Fifty-ninth Congress.

He resumed the practice of law until his death in Perryville, Missouri, March 13, 1934.