Kalinderu stayed on as Carol's legal adviser, also helping him in direct negotiations with the National Liberal and Conservative political machines, and was several times considered for the office of Prime Minister.

As administrator for the crown, Kalinderu enacted his vision of rural improvement, setting up model farms and a cottage industry, promoting literacy and the arts, and encouraging entrepreneurship.

In addition to his agrarian project and his social work, Kalinderu played a significant part in promoting mountaineering and modern forestry, set up the resort of Bușteni, and created his own art museum.

[7] 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,[8] advancing to paharnic in the 1850s.

[9] His son would later falsely claim that the Kalenderoglus played a part in the Wallachian Revolution of 1848,[10] although Lazăr is known to have held relevant positions in the National Party in 1857, briefly serving as its chairman alongside Constantin A.

[11] 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.

[28] 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.

[10] Brătianu, who had taken over as Prime Minister, arrived in Berlin to personally supervise the negotiations, reportedly because the hastiness on the German side to seal off the deal "inspired in him grave disquietude".

[3] In June 1884, Kalinderu was named the first administrator of crown domains, which had been set aside by organic law,[5][10][32] resigning from his position at the railways company in December 1885.

[33] Owned by the state and managed by the House of Hohenzollern (through Kalinderu), the domains originally included twelve country estates and two mountains of the Southern Carpathians: Clăbucetul Taurului and Caraiman.

[4] In 1891, following the resignation of a Conservative Party government under Gheorghe Manu, Carol reportedly proposed Kalinderu as Prime Minister of an independent cabinet.

[43] Kalinderu also reported to his former Berlin colleague Sturdza, by then the National Liberal Prime Minister, that Carol had dismissed him,[44] then negotiated a reunification of the Conservatives and Junimea defectors, prompted by the king's wish to have a stable government party.

[60] He also published an homage to Stephen the Great, medieval Prince of Moldavia, studies of succession to the Romanian throne, and an academy-sanctioned biography of Melchisedec Ștefănescu.

[63] Another visitor, André Bellessort, joked that the perpetually youthful "Mr. Kalindero" resembled "a rustic god", a patron of the farmers with "nitrogen eyes".

[67] As chemist Amuliu Proca notes, Kalinderu turned the domains into an "institution for defeating poverty, a factor in educating and culturally improving the villages".

[49] Following Julius Kühn, Kalinderu insisted that the precondition of a "rational economy" was good livestock, so he inaugurated a freely accessible breeding program, also providing tenants with cultivars, or with beekeeping and sericulture implements.

[71] A significant portion of his time was spent on teaching peasants to diversify their diet, including providing hired hands with daily rations of vegetables, meat and milk.

[72] In 1901, agronomist Constantin Sandu-Aldea acknowledged that there was a stark difference between "the mass of cultivators, who fall behind progress", and those living and working on crown lands.

[76] However, his attempts to uproot alcoholism and promote personal hygiene had mixed results, according to the left-wing Mihail Sadoveanu, who noted, sarcastically, "true enough, these days taverns have been replaced by bathhouses and libraries.

[15] At the Progress in Forestry Society, he condemned the peasants' belief that "the state has a duty to provide them with land", and insisted that the root cause of the revolt was their failure to accept modernity and practicality.

"[80] Mediating between the Conservatives and the king, Kalinderu obtained guarantees against the reform, although he and the crown advocated "a credit union under the control of the state, permitting peasants to accumulate more land of their own.

[83] Kalinderu's other ambitious ideas manifested themselves erratically, including a project for a girls' boarding school in Turnu Măgurele, the "Oteteleșanu Institute",[84] which he launched without the academy's approval.

[86] From July 1906 onward,[87] his other pet project was art collecting, with the goal of setting up a museum at his villa on Vasile Sion Street, near the Cișmigiu Gardens.

"[88] Similarly, critic George Oprescu suggests that Ioan's taste in art was eclipsed by that of his physician brother Nicolae, who selected "all that is best" in the Kalinderu collection.

[94] Reportedly, he worked for free at the crown domains, refusing to collect his salary: "The only rewards he desires are peasant blessings and his playing billiards with His Majesty.

[97] The future Queen Marie was much amused by Kalinderu, describing him as "little, round, with a short beard and a pronounced Semitic nose; one of his eyes sparkled wickedly, showing an unusually sharp intelligence".

[31][98] She recalled a visit with him to Windsor Castle, where "it was truly amusing to see the short gentleman very pleased with himself, catching everything with his glimpse, weighing, judging, taking the measure of people and things, with that small, penetrating, almost wicked eye".

[101] During the peasants' revolt, Furnica published a cartoon showing Kalinderu as a personification of Cajolery, interposing himself between Carol and The Truth (personified by a tenant farmer);[102] issues of that period were confiscated by the Ministry of Internal Affairs.

[10][56][111] Argetoianu claims that Kalinderu had prepared a will benefiting his favorite institution, but ended up "quarreling with the Academy one year before his death", and failed to clarify his intentions in due time.

[116] In January 2014, the centennial of Kalinderu's death was solemnly marked by the General Association of Romanian Engineers, which discussed opening up a museum of the crown domains in Segarcea.