St Zygmunt Szczesny Felinski was born on 1 November 1822 to Gerard Felinski and Eva Wendorff, in Wojutyn, Volinia (present-day Ukraine), then Russian territory. He was the third of six children, of whom four survived.

Felinski was raised with faith and trust in Divine Providence, love for the Church and for Polish culture. His father died when he was 11 and in 1838 the Russians exiled his mother to Siberia for "involvement in patriotic activity" that is, working for farmers' rights.

Felinski studied mathematics at the University of Moscow (1840-44) and in 1847 went to the Sorbonne University and the Collège de France in Paris to study French literature. He was in touch with all the important Polish emigrants and took part in the unsuccessful Revolt of Poznan.

In 1851 he returned to Poland. He entered the diocesan seminary at Zytomierz and studied at the Catholic Academy of St Petersburg. He was ordained a priest on 8 September 1855 and assigned to the Dominican Fathers' Parish of St Catherine of Siena in St Petersburg until 1857, when the Bishop appointed him spiritual director of the Ecclesiastical Academy and professor of philosophy. In 1856 he founded a charitable organization for the poor, and in 1857, the Congregation of the Franciscan Sisters of the Family of Mary. On 6 January 1862, Pope Pius ix appointed Fr Felinski Archbishop of Warsaw and he was consecrated on 26 January 1862 in St Petersburg. He arrived in Warsaw on 9 February 1862.

The Russians had brutally suppressed the Polish uprising in this city in 1861. On 13 February 1862, the new Archbishop reconsecrated the Cathedral of Warsaw, which had been desecrated by the Russian troops. Three days later he opened all the churches with the solemn celebration of the "Forty Hours" Devotion.

Zygmunt Felinski was Archbishop of Warsaw in the turbulent period from 9 February 1862 to 14 June 1863. Unfortunately, he met with distrust on the part of some, even clergy, since the Russian Government had led people to believe that he was collaborating secretly with the Government. The Archbishop always showed clearly he was at the service of the Church alone and strove to eliminate government interference in the internal affairs of the Church. In reforming the diocese he regularly visited all the parishes and charitable organizations on order to address their needs better. He reformed the syllabus of the Ecclesiastical Academy of Warsaw and of the diocesan seminaries, giving a new impetus to the spiritual and intellectual development of the clergy. He took steps to obtain the release of priests in prison and he encouraged them to proclaim the Gospel publicly, to catechize their parishioners, to open parish schools and to educate a new generation that would be devout and honest. He also cared for the poor and opened an orphanage in Warsaw that he entrusted to the Sisters of the Family of Mary.

Archbishop Felinski strove to prevent the nation from making rash moves and, as a protest against the Russians' bloody repression of the "January Uprising" in 1863, resigned from the Council of State and wrote to the Emperor Alexander ii, urging him to put an end to the violence. He likewise protested against the hanging of Fr Agrypin Konarski, a Capuchin and chaplain of the "rebels". His courageous actions soon led to his exile to Siberia.

On 14 June 1863, he was deported to Jaroslavl, where he spent the next 20 years, deprived by the Tsar of all contact with Warsaw. Yet he managed to organize works of mercy for his fellow prisoners, especially the priests, and somehow succeeded in collecting enough funds to build a Catholic church. The people were impressed by his spirituality and nicknamed him the "holy Polish Bishop". Archbishop Felinski was released on 15 March 1883 and Leo XIII transferred him from the See of Warsaw to the titular See of Tarsus. For the last 12 years of his life he lived in semi-exile, serving as parish priest in south-eastern Galizia at Dzwiniaczka, among farmers of Polish and Ukrainian origin. As chaplain of the public chapel of the local manor, he undertook an intense pastoral work. He set up the first school and a kindergarten in the village at his own expense.

He also built a church and convent for his Franciscan Sisters of the Family of Mary, and found the time to prepare for publication the works he had written in exile. He died in Kraków on 17 September 1895 and was buried there on 20 September; the following month his mortal remains were translated to Dzwiniaczka, and in 1920, to Warsaw. Here, on 14 April 1921, they were solemnly interred in the crypt of St John's Cathedral where they are venerated today. John Paul II beatified him in Kraków, Poland, on 18 August 2002.