[1] He was a star in Abraham Goldfaden's first Bucharest-based theater troupe — and the playwright wrote the title role of Shmendrik for him.

After immigrating to the United States, he eventually founded the Rumanian Opera House on New York City's Lower East Side, one of the great venues of Yiddish theater.

His father died when he was nine years old, and his mother received assistance for the family from the local Jewish community.

In 1874, Mogulesko performed with a visiting French operetta troupe, where he met Lazăr Zuckermann, Simhe Dinman, and Moses Wald.

As his voice changed, Mogulesko worked for two years knitting, then returned to sing for Cuper at the synagogue, serving as an 18-year-old choral director.

In 1877 Abraham Goldfaden arrived in Bucharest with his less-than-year-old troupe, the first professional Yiddish theater company.

Describing how Goldfaden came to engage Mogulesko as an actor, Nahma Sandrow remarks: "Meshoyrerim were sophisticated musically, and were notorious for being freethinking and irreverent.

As soon as Goldfadn [sic] arrived in town he heard about a young cutup who was the life of local parties, imitating scenes from Rumanian comedies and mimicking the dignified cantor he sang for.

In New York, he introduced Jacob Adler and Keni Lipzin to the American stage, who both became highly influential.

In June 1906, Mogulesko made a successful return tour to Romania, reviving Yiddish theater there after a decade of doldrums.

[1] He brought to Romania some of the hits of New York Yiddish theater, most of which were new in that venue: Shaykevich-Shomer's Di Emigrantn ("The Emigrants"), and Yekl Baltakse, Dos Groyse Glik ("Big Luck") by Kornblatt, and Der Umbakanter ("The Unknown") by Jacob Gordin.

Writing of Mogulesko's troupe in Romania in 1884, and probably referring to the plays of Moses Horowitz and Joseph Lateiner, Dr. Moses Gaster was generally impressed: Above all, we must assert that Jewish theater, through the pieces played on its stage, has indeed an educative and moral scope, because on the one hand it represents scenes from our history known by only a tiny minority, refreshing, therefore, secular memory; on the other hand, it shows us our defects, which we have like all men, but not with a tendency to strike at our own immorality with a tendency towards ill will, but only with an ironic spirit that does not wound us, as we are wounded by representations on other stages, where the Jew plays a degrading role.