Calogero served for three years in the United States Army as a military police officer and in the Judge Advocate General's Corps. He was briefly a law clerk for the Orleans Parish Civil District Court and from 1958 to 1972, was in the law firm of Landrieu, Calogero, and Kronlage. His senior partner was his fellow DemocratMoon Landrieu, the former mayor of New Orleans. He was first elected to the Louisiana Supreme Court in 1972 and reelected in 1974, 1988, and 1998. He retired at the end of 2008, a record career of thirty-six years. While on the bench, he participated in more than six thousandoral arguments and published opinions. He personally authored more than one thousand majority opinions, concurrences, and dissents. As Chief Justice, he oversaw the establishment of the Louisiana Indigent Defender Board, improvements to the juvenile court system, development of a new lawyer disciplinary code, the strengthening of the judicial disciplinary system, the adoption of strategic plans for the three-tiered court system, implementation of a uniform pay plan for the state appellate courts, and establishment of the Supreme Court's community relations department. Calogero's most visible achievement is the renovation of the New Orleans Civil Court Building at Royal and Conti Streets in the French Quarter. Built in 1908 for the Supreme Court and many smaller courts and state offices, the Royal Street courthouse had been vacated by the state courts in 1958. The building suffered serious neglect and was in danger of being torn down or altered significantly for other purposes. In the 1980s, the Supreme Court began to explore the possibility of returning to its 1908 building, and throughout the 1990s Calogero fought to win over the legislature to the idea and to acquire state funding for the project. The renovation was completed in 2004, and the Supreme Court and its associated agencies moved back into their former home. The building now lends its dignity to the proceedings of the court and its vitality to the French Quarter. On October 3, 1998, Calogero faced opposition from RepublicanCharles Cusimano of Metairie in Jefferson Parish, a former member of the Louisiana House of Representatives and then a state district court judge. Calogero led in the nonpartisan blanket primary with 77,766 votes, and Cusimano polled 64,711 ballots. A third candidate held the remaining 8 percent of the vote. Cusimano decided not to contest the general election, and Calogero held the seat by default for another ten years.