A former prime minister, the mayor of Montreal and hundreds of the faithful gathered at St. John Brebeuf Parish in LaSalle Sunday afternoon to celebrate one of Montreal's best-known – and best-loved – Catholic priests.

Fr. John Walsh celebrated the 50th anniversary of his ordination.

In that time, Walsh said he has seen it all, and faced moments when his faith was tested.

“The more we can give of ourselves and be generous to other people, we'll have a chance that the world will actually be a beautiful world in which to live,” he said.

At the celebration Sunday, Walsh was celebrated by political leaders, including former prime minister Paul Martin and Montreal Mayor Denis Coderre.

“It's his generosity and his intuition about people. It's quite clear I am a huge fan of his,” said Martin.

“When we have issue of radicalization and prevention, when I put together my summit on living together, that's his value, to bring people together,” said Coderre.

Some of Montreal's religious leaders were also there to celebrate Walsh’s lengthy career.

“Father John is one of the unique persons when it comes to fighting Islamophobia and anti-Semitism. He did a lot of work within the communities and most likely three-quarters of the rabbis I know are through him,” said Imam Salam Elmenyawi, president of the Muslim Council of Montreal.

His work with the Jewish community started in the 1970s, when he studied at Hebrew University in Jerusalem, and continues to this day.

“He reached out to me and asked if we could conduct a model Passover Seder together because his community wanted to know more about Jewish rituals and customs, and I said, yeah sure, you can do it on one condition: that I come along and do it with you, and since then, fast friends,” said Gideon Zellermeyer, cantor of the Shaar Hashomayim.

He was a priest here at St. John Brebeuf Parish in LaSalle for a decade before he retired in 2010.

Six years later, there's no shortage of parishioners who admire him, including his sister Marlene Robitaille.

“He baptized my four children. He baptized them, married them, he buried my mother, father and my husband 15 years ago, so he's there whenever we need him,” she said.

The event Sunday also served as the launch of his autobiography, ‘God is Calling, Don’t Leave him on Hold.’

“I think one of the great professors of our time, Hans Kunz, said it well; if there isn't peace among religions, there won't be peace in the world,” said Walsh.

In his book and at the mass, Walsh spoke of a spiritual revolution that he feels he has witnessed over five decades in the church, and is intent on working towards more many years to come.