Born in Bucharest on December 28 or 29, 1840, his father was Lazăr (Lazaros) Kalenderoglu (or Calenderoglu).
Of possible Smyrniote origin, the family functioned as one of the largest banking and exporting institutions in Wallachia, and then in the United Principalities.
Lazăr had risen into the ranks of Wallachia's boyar nobility: joining the Bucharest local government in 1838, 1844, and 1847, he was awarded the title of pitar, advancing to paharnic in the 1850s.
His son would later falsely claim that the Kalenderoglus played a part in the Wallachian Revolution of 1848, although Lazăr is known to have held relevant positions in the National Party in 1857, briefly serving as its chairman alongside Constantin A. Crețulescu.
The last-ever tenant and tax collector of Predeal customs, Kalenderoglu had his estate in Olt County, outside Colonești, reduced during the land reform of 1864.
Another of his estates, at Bălcești, was repurchased by the Bălcescu boyars.
However, he still left Ioan the manor of Schitu-Greci.

Although a Wallachian native and relatively assimilated, Lazăr was sometimes regarded as an ethnic Turk, owing to his Turkish-sounding surname.
He identified as Greek-Romanian and, as late as 1879, was ktitor of an eponymous Greek Orthodox church in Bucharest.
His fully assimilated son later barred the Greek colony from attending the church, and rededicated it to Romanian Orthodoxy.
Ioan and his brother Nicolae were educated in Greek, before graduating high school in Bucharest.
Ioan studied law at the University of Paris.
Taking his license degree with a study of dowries in Roman law (1860), and earning a doctorate with a thesis on ex post facto laws (De la non-rétroactivité des lois, 1864), he returned home to take up positions as a judge, serving as the first president of Bucharest Tribunal.
He then became a counselor with the Court of Cassation.

From 1872, the Ministry of Justice employed him as an adviser for penal reform, alongside Vasile Boerescu, Nicolae Mandrea, Grigore Păucescu, Mihail Pherekyde and Grigore Triandafil.
Boerescu referred to Kalinderu as "a man of the new world, with very progressive ideas, and an excellent jurisconsult."
At the time, his family was involved with the liberal-radical movement.
Brother Nicolae, a Paris-trained physician, became one of the founders of the National Liberal Party in 1875.
The aged Kalenderoglu was founder of Creditul Rural, a credit union for the benefit of peasants, alongside major liberal figures.

In 1875, Ioan also joined the National Liberals in opposing the concession of the Predeal railway to the Englishman George Crawley; alongside party leaders Ion Brătianu and Dimitrie Sturdza, he created an investment firm that tried to compete with Crawley for the contract.
Kalinderu advanced on the public scene following the Strousberg Affair, during which Romania purchased back her railways from the bankrupt Prussian investor B. H. Strousberg.
In February 1880, he and Strudza were dispatched to Berlin to negotiate payment of Strousberg's government bonds with the Imperial German authorities.
In April, Domnitor Carol I appointed him on the Princely Commission for the Administration of Railways, the embryonic Căile Ferate Române.
The other members of this directorial triumvirate were Eugeniu Stătescu and Ștefan Fălcoianu.
Kalinderu maintained his office in Berlin until 1882, representing the newly established Kingdom of Romania.
In 1882, he published a French-language tome dealing specifically with the legal implications of the Strousberg Affair: De la compétence des tribunaux et particulièrernent des tribunaux prussiens dans toute contestation relative aux biens mobiliers qu'un état étranger peut posséder en Prusse.

As noted at the time by Titu Maiorescu, Kalinderu was responsible for placing his government in a humiliating position, and it was surprising that such a mission was entrusted to so unqualified an individual.
Brătianu, who had taken over as Prime Minister, arrived in Berlin to personally supervise the negotiations, reportedly because the hastiness on the Ge
Born in Bucharest on December 28 or 29, 1840, his father was Lazăr (Lazaros) Kalenderoglu (or Calenderoglu). Of possible Smyrniote origin, the family functioned as one of the largest banking and exporting institutions in Wallachia, and then in the United Principalities. Lazăr had risen into the ranks of Wallachia's boyar nobility: joining the Bucharest local government in 1838, 1844, and 1847, he was awarded the title of pitar, advancing to paharnic in the 1850s. His son would later falsely claim that the Kalenderoglus played a part in the Wallachian Revolution of 1848, although Lazăr is known to have held relevant positions in the National Party in 1857, briefly serving as its chairman alongside Constantin A. Crețulescu. The last-ever tenant and tax collector of Predeal customs, Kalenderoglu had his estate in Olt County, outside Colonești, reduced during the land reform of 1864. Another of his estates, at Bălcești, was repurchased by the Bălcescu boyars. However, he still left Ioan the manor of Schitu-Greci.
Although a Wallachian native and relatively assimilated, Lazăr was sometimes regarded as an ethnic Turk, owing to his Turkish-sounding surname. He identified as Greek-Romanian and, as late as 1879, was ktitor of an eponymous Greek Orthodox church in Bucharest. His fully assimilated son later barred the Greek colony from attending the church, and rededicated it to Romanian Orthodoxy. Ioan and his brother Nicolae were educated in Greek, before graduating high school in Bucharest. Ioan studied law at the University of Paris. Taking his license degree with a study of dowries in Roman law (1860), and earning a doctorate with a thesis on ex post facto laws (De la non-rétroactivité des lois, 1864), he returned home to take up positions as a judge, serving as the first president of Bucharest Tribunal. He then became a counselor with the Court of Cassation.
From 1872, the Ministry of Justice employed him as an adviser for penal reform, alongside Vasile Boerescu, Nicolae Mandrea, Grigore Păucescu, Mihail Pherekyde and Grigore Triandafil. Boerescu referred to Kalinderu as "a man of the new world, with very progressive ideas, and an excellent jurisconsult." At the time, his family was involved with the liberal-radical movement. Brother Nicolae, a Paris-trained physician, became one of the founders of the National Liberal Party in 1875. The aged Kalenderoglu was founder of Creditul Rural, a credit union for the benefit of peasants, alongside major liberal figures.
In 1875, Ioan also joined the National Liberals in opposing the concession of the Predeal railway to the Englishman George Crawley; alongside party leaders Ion Brătianu and Dimitrie Sturdza, he created an investment firm that tried to compete with Crawley for the contract. Kalinderu advanced on the public scene following the Strousberg Affair, during which Romania purchased back her railways from the bankrupt Prussian investor B. H. Strousberg. In February 1880, he and Strudza were dispatched to Berlin to negotiate payment of Strousberg's government bonds with the Imperial German authorities. In April, Domnitor Carol I appointed him on the Princely Commission for the Administration of Railways, the embryonic Căile Ferate Române. The other members of this directorial triumvirate were Eugeniu Stătescu and Ștefan Fălcoianu. Kalinderu maintained his office in Berlin until 1882, representing the newly established Kingdom of Romania. In 1882, he published a French-language tome dealing specifically with the legal implications of the Strousberg Affair: De la compétence des tribunaux et particulièrernent des tribunaux prussiens dans toute contestation relative aux biens mobiliers qu'un état étranger peut posséder en Prusse.
As noted at the time by Titu Maiorescu, Kalinderu was responsible for placing his government in a humiliating position, and it was surprising that such a mission was entrusted to so unqualified an individual. Brătianu, who had taken over as Prime Minister, arrived in Berlin to personally supervise the negotiations, reportedly because the hastiness on the Ge
Ioan Kalinderu