Carlo Laurenzi was born in Perugia, and studied at the University of Perugia, from where he obtained his doctorates in theology (1 December 1843) and in canon and civil law (17 January 1845).

He was ordained to the priesthood on 23 September 1843, and finished his studies in 1845. Laurenzi was later made a canon of the cathedral chapter of Perugia in June 1846, the pro-vicar general of Perugia in February 1847, and a Privy Chamberlain supernumerary of His Holiness in 1853. He also served as President of the Theological College at his alma mater of the University of Perugia, and became a canon archpriest in 1857.

On 22 June 1877, Laurenzi was appointed Auxiliary Bishop of Perugia and Titular Bishop of Amathus in Palaestina by Pope Pius IX, receiving his episcopal consecration from Cardinal Gioacchino Pecci, the future Pope Leo XIII. He was later named an Assistant at the Pontifical Throne on 13 March 1878, Auditor Sanctissimi on 15 May 1879, and Assessor of the Sacred Congregation of the Supreme Roman and Universal Inquisition on 30 March 1882.

Pope Leo secretly (in pectore) elevated him to the College of Cardinals in the consistory of 13 December 1880, eventually publishing him as cardinal priest of Basilica di Sant'Anastasia al Palatino on 10 November 1884. Laurenzi was appointed Secretary of Memorials of His Holiness on 25 April 1885, and served as Camerlengo of the Sacred College of Cardinals from 11 February to 30 December 1889. On 14 March of that same year, he was made prefect of the Sacred Congregation of Rites.

Laurenzi died in Rome, at age 74. He lay in state in his cardinalatial church before being buried at the chapel of the Congregation for the Propagation of the Faith in the Campo Verano cemetery.

• Catholic-Hierarchy ^{[self-published]}
• Cardinals of the Holy Roman Church