Matty Robson secured Carlisle's first win of the season with a second-half header, leaving the neat but punchless Blades still seeking their first away success in League One.
Clear-cut chances were few and far between in a first half stalemate, although Carlisle had a penalty appeal turned down in the 18th minute when Lewis Guy was sent sprawling by visiting goalkeeper George Long. The referee's decision was a goal kick.
The best opportunity of the opening 45 minutes fell to Blades' defender Neill Collins, who got up highest to reach Jose Baxter's right-wing corner.
The header from six yards had plenty of power, but Collins was unable to keep the ball down and it flew over the crossbar to the relief of the Carlisle defence.
Carlisle broke the deadlock in the 54th minute when the Blades failed to deal with James Berrett's corner and Matty Robson was on hand to nod the ball over the line from close range. His effort only just crossed the goalline and was awarded on the signal of the referee's assistant.
Blades substitute Callum McFadzean sparked a response from Sheffield and his low cross from the left skidded across the six-yard box and the winger then laid on a chance for skipper Michael Doyle, who lifted his shot high over the crossbar from 12 yards.
But Carlisle held on well for their first home clean sheet of the season, while Troy Archibald-Henville nearly made it safe when he skewed a close-range header wide in the dying minutes.