Massa interned at the South Bend Tribune and Milwaukee Journal Sentinel before becoming a sportswriter for the Evansville Courier & Press, where he also covered the courts and local government.

Massa was an assistant United States attorney in the Southern District of Indiana, where he earned the Inspector General's Integrity Award from the Department of Health and Human Services.

[4][3] In 2018, Massa authored an opinion of the court holding that Indiana's shoreline on Lake Michigan was open to all, barring adjacent property owners from excluding others from such land.

[5] August 23, 2023, Justice Massa joined the 4-1 decision without written opinion, putting Indiana's near total abortion ban immediately into effect.

The trial court also found the county Republican chair’s refusal to certify Rust’s membership was invalid under the Affiliation Statute according to canons of statutory interpretation.

Explaining that Rust does not have a “fundamental right” to run for U.S. Senate as the Republican nominee but “still enjoys a statutory right to appear on the general-election ballot as an independent, Libertarian, or write-in candidate,” the court determined that the Affiliation Statute “imposes a reasonable and nondiscriminatory restriction on Rust’s right to be on the primary election ballot.”[6] The court then concluded that the state’s “important regulatory interests”—including “safeguarding parties from forced inclusion of unwanted members and candidates,” “sustaining the identifiability of political parties,” “fostering the health and ‘stability of their political systems,’” and “protect[ing] the integrity of the election process”—justify the restriction.