[1] Randa was nominated by President George H. W. Bush on April 9, 1992, to a seat on the United States District Court for the Eastern District of Wisconsin vacated by Judge Robert W. Warren; he was confirmed by the United States Senate by unanimous consent on August 11, 1992, and received commission on August 12, 1992.

[1] In 2002, Randa was appointed by Supreme Court Chief Justice William H. Rehnquist to serve on the Codes of Conduct Committee of the United States Judicial Conference.

He ruled that Congress could not use its constitutional authority under the Commerce Clause to regulate abortion protests, "a private activity wholly intrastate in character, non-violent by description and definition, without any commercial aspect, the control of which historically and traditionally rested within the domain of local and state authorities, and which has no direct effect on interstate commerce but instead affects an activity found by Congress to be within 'the stream of interstate commerce ...'"[5] His ruling was reversed by the Seventh Circuit Court of Appeals.

[7] In 2009, in Flying J. v. Van Hollen, Randa ruled that Wisconsin's minimum markup of 9.18% on gasoline as required by the Unfair Sales Act was unconstitutional.

[9] The Wisconsin Petroleum Marketers & Convenience Store Association ("WPMCA") moved to intervene post-judgment and to appeal Randa's ruling.

In 2010 the 7th Circuit Court of Appeals overruled Randa's decision and found Wisconsin's Unfair Sales Act to be constitutional.

Randa ordered the state to begin using licensed practical nurses or medical personnel with equivalent training to distribute and administer prescriptions, instead of using correctional officers.

[12] On appeal, the Seventh Circuit agreed that the indenture was an unapproved management contract, but remanded for further proceedings to determine whether any collateral documents could support the waiver of sovereign immunity.

[13] In 2014, Randa ordered that evidence collected by prosecutors in a campaign finance investigation regarding alleged unlawful "coordination" by advocacy groups opposing the 2012 recall election of Wisconsin Governor Scott Walker be destroyed and the probe be halted.

One day later, a 7th Circuit Court of Appeals panel issued a stay of his ruling on procedural grounds, returning the case to Randa to determine whether the prosecutors' motions are frivolous.

[14][15] On October 14, 2014, Randa issued a preliminary injunction, directing Milwaukee County District Attorney John T. Chisholm and the state Government Accountability Board to not enforce a controversial section of Wisconsin campaign finance law, which he ruled was in contravention of the First Amendment.