Moșoiu was born in 1868 in the village Újtohán, at the time in Austria-Hungary, now Tohanul Nou, part of Zărnești, Brașov County, Romania.

In 1891 he got into conflicts with fellow officers after he cried foul at the Hungarians, making demands for the equal rights of the ethnic Romanians within the Habsburg Empire.

He then crossed the Bucegi Mountains into Romania, arriving in Sinaia, where he surrendered to the authorities, asking to join the Romanian Army ranks.

[3] He saw action in the military campaign in Bulgaria during the Second Balkan War and on 1 October 1913, he was appointed commander of the 30th Regiment Vânători at Câmpulung, holding the rank of lieutenant-colonel.

King Ferdinand called for the mobilization of the Romanian army and ordered it to attack by crossing the Carpathian Mountains into Transylvania.

At the end of November 1918, the 7th Infantry Division under the command of Moșoiu crossed the Carpathians, coming from Piatra Neamț and advancing though the Prisăcani Valley towards Borszék, Maroshévíz, and Szászrégen.

He entered Nagyvárad on 20 April alongside General Ștefan Holban, and took control of the administration of the city that day.

Soon after, the bulk of the Romanian troops arrived in the Budapest and a parade was held through the city center in front of their commander, General Moșoiu.

From January 1922 to October 1923, he was Communications Minister, supporting administrative and fiscal autonomy for Căile Ferate Române railway.

[11] During the 1922 campaign, his rival, Aurel Vlad [ro] of the Romanian National Party, was detained for three hours while en route to a rally in Orăștie, for purposes of intimidation.

[13] A bust of him, sculpted by Teodor Zamfirescu, was unveiled in Oradea in 1992; the monument was rehabilitated in 2019, on the occasion of the centenary of Moșoiu's troops taking control of the city and establishing Romanian administration there.

[14] In 2007, on the 75th anniversary of his death, a bust of Moșoiu was erected in Bran, Brașov County; the inaugural ceremony was attended by then-President Traian Băsescu.