After completing his undergraduate studies, Bruning attended the University of Nebraska-Lincoln College of Law, where he received his Juris Doctor in 1994.

[11][12][13][14] In August 2011, the Omaha World-Herald reported that Bruning had purchased a lakeside house valued at $675,000 near the Platte River in partnership with two Nelnet executives, almost a year after he and his office had been accused of acting favorably toward the student loan company by not enforcing payment of a $1 million judgment awarded to the State of Nebraska when Nelnet was under fire for alleged improper business practices.

His office led the legal challenge to the federal Patient Protection and Affordable Care Act's provision regarding employer-paid health insurance requirements related to abortion.

Bruning and Pruitt argued that the Colorado measure violated the Supremacy Clause of the U.S. Constitution, since the U.S. Congress had enacted the 1970 Controlled Substances Act, which imposed a nationwide ban on marijuana.

Later that year, however, Hagel announced that he would not seek reelection; soon thereafter, former Nebraska Governor Mike Johanns joined the race for the now-open seat.

[23][24][25] In late 2010, Bruning announced that he would run in the 2012 election for the U.S. Senate seat held by Democrat Ben Nelson, whose approval ratings in Nebraska had plummeted after he provided the 60th and final vote necessary to break a Republican filibuster and pass the Patient Protection and Affordable Care Act.

Bruning was seen as the strong front-runner in the Republican primary race; former Attorney General and current State Treasurer Don Stenberg, favored by the conservative Tea Party movement, was seen as his strongest challenger.

Shortly before the election, the political action committee Ending Spending, financed by Omaha businessman Joe Ricketts, ran a television ad attacking Bruning for buying a lake house together with two executives of Lincoln student-loan firm Nelnet less than a year after Bruning, in his capacity as attorney general, had sought to waive a $1 million penalty against the company.

In the primary election, voters delivered an unexpected victory to dark-horse candidate Deb Fischer, who won 41% of the vote to Bruning's 36% and Stenberg's 19%.