In 1984, the Hudson County Board of Chosen Freeholders renamed the building in honor of Supreme Court Justice William J. Brennan Jr.

Roberts delegated the assignment of artwork to the muralist Francis David Millet,[7] noted for his work as decorations director for the 1893 World's Columbian Exposition in Chicago; Millet assigned himself two lunettes on the third floor and a dozen small panels in the second floor corridors.

[7] The Tudor-style legislative chamber of the Board of Freeholders on the second floor was adorned with murals by Howard Pyle depicting early life of the Dutch and English in New Jersey.

Standing in the great central court, one looks up the three stories of the magnificent rotunda to a dome whose outer rim is painted with the signs of the zodiac and whose center is an eye of stained glass worthy of Tiffany.

[10] Conrad led a citizens group that lobbied for the preservation of the building, and got it listed on the National Register of Historic Places.

[11] The award-winning restoration project resulted in the courthouse being reopened in 1985 for the use of the civil courts and other county offices.

[12] Following the 1989 Supreme Court decision in Texas v. Johnson, which Brennan authored, veterans groups petitioned unsuccessfully to have the name removed, but the Freeholders unanimously voted to retain the name.