The road to ordination contains years of study, discernment, and formation. As the day approached, DeSio was pleasantly surprised by the way he felt the Lord moving.

“God poured out much grace: I found myself with more peace and joy than I have ever had, which I received as an affirmation that this is God’s will for my life,” said DeSio. 

“In the moments leading up to the ordination Mass itself, I was filled with great confidence that I am answering the Lord’s call. While I expected nerves to kick in, it was quite the opposite. I was filled with incredible peace.”

That same peace remained as the liturgy began, allowing him to absorb the gravity of the moment he had spent so much time preparing for.

“It was a lot to take in,” DeSio recalled.  “I don’t think I have ever been that immersed in the present moment before in my entire life. Time itself seemed to stop, and not just because the liturgy is longer than usual. Interiorly, I was filled with a certain readiness and willingness to lay down my life to serve Jesus and the Church in the sacrament of Holy Orders.”

For DeSio, his diaconate ordination was not an endpoint, but a long-awaited milestone on his path to priesthood.

The transitional diaconate is the final major step before priesthood. When a seminarian is ordained a transitional deacon, he officially becomes a member of the clergy and begins to serve in ministry while continuing preparation for priesthood. During this period, they contribute to the life of the Church in the same way as a permanent deacon does: they preach homilies, baptize people into the Church, witness marriages, preside at funerals, and assist at Mass.  

This period is a combination of practical training and a spiritual transition for seminarians. During the ordination to transitional diaconate, they profess promises of celibacy, prayer, and obedience to the bishop. The time spent as a deacon provides an opportunity to live out these promises.

Long before seminary, the foundations of his vocation were already laid. Growing up in a large Catholic family as one of six children, faith was a constant presence in his home and upbringing. It was during his time in college that he heard God calling him to be a priest.

“During my second year of college, I was studying to be a firefighter,” said DeSio. “Until then, I assumed my vocation was marriage. I prayed one day and experienced an invitation from God to sacrifice my own plans of having a career and a family of my own to lay down my life by becoming a priest. My uncle, Father Gregg Tottle, was the first person I told; he encouraged me to check out the seminary. The Lord has given greater clarity over the years, so here I am!”

The years spent in seminary thus far only deepened his sense of the vocational call, shaping his spiritual life and his character.

“The education that he received in seminary has substantially helped his growth as an individual and as a man dedicated to the Lord,” said Father Tottle, DeSio’s uncle and priest of the Diocese of Saint Petersburg.

Watching that maturation over the years, Father Tottle has seen certain qualities consistently stand out as strengths that he believes will continue to assist him on his journey to priesthood.

“I believe he has a strong commitment to prayer. Although he and his two younger brothers joined me for a vacation, he maintained his prayer throughout and it took precedence over all other vacation activities,” Father Tottle recalled. “I also see the ease at which he witnesses to the faith, consistently seizing every opportunity to evangelize.”

For many newly ordained clergy, the promises made during diaconate ordination are when the weight of the moment becomes the most real. DeSio recalled feeling this strongly.

“I have heard many priests and deacons say this, and I definitely agree,” he said. “The responsibility that I have undertaken is serious. Yet, I am filled with trust and confidence in God and am grateful to St. Vincent de Paul Regional Seminary for preparing me to make this life-long commitment.”

Among the many moments of the liturgy, one portion stayed with him the most.

“In the Promise of the Elect, those to be ordained respond, ‘I do.’ However, when the bishop asks, ‘Do you resolve to conform your manner of life always to the example of Christ, whose Body and Blood you will handle at the altar?’ The response is: ‘I do, with the help of God.’ I find this particularly meaningful because of its emphasis on God’s help: on His grace. It is only by God’s grace that I am able to fulfill these promises.”

The joy of ordination continued into DeSio’s first Mass as a deacon, where one presence at the altar carried special meaning: his uncle. Father Tottle has watched his nephew’s vocation flourish and faith life develop over the years and now had the opportunity to celebrate Mass with DeSio assisting alongside him.

“I felt very honored to be asked to be the main celebrant,” said Father Tottle. “I also was pleased to celebrate with the rector and president, Father Alfredo Hernandez, and the other priests who concelebrated. I could not be happier to witness Mark’s joy as well as the joy of the family to be there for the Mass.”

For DeSio, this incredible experience of Mass carried many firsts. This was the moment that he assisted at Mass as a deacon for the first time, assisted his uncle as a fellow member of the clergy, and preached the first of many homilies he will give over the course of his ministry as deacon and priest.

“I was aware of how uncommon this experience is,” he said. “Not everyone has a priest for an uncle! Being there at his side with many other family members present in the chapel was a tremendous gift, as his vocation is, to our family. I am grateful that he was the celebrant for the first Mass I assisted at as a deacon.”

With diaconate ordination behind him, DeSio now looks ahead with enthusiasm to a year of ministry marked by new responsibilities and exciting opportunities to more deeply participate in the Mass.

“Being able to raise the chalice of the Precious Blood as the priest raises the paten with the consecrated Host is powerful!” he said. “After Mass every day this year, I have been praying Psalm 116:12-13 which says, ‘How can I thank the Lord for his goodness to me? The cup of salvation I will raise.'”

Even amid the joy of this milestone, both DeSio and those closest to him know priesthood is on the horizon.

“I am looking forward to growing in my capacity to give myself to the Church,” said DeSio. 

“As a deacon, there are more ways that I can serve in a parish now. For example, I can preach, marry couples, and bury the dead. I am looking forward to these and other ways of serving that will be a great way for me to expand my capacity to give myself in the parish so that I will be better prepared to give myself fully in the priesthood.”

As ordination to the priesthood draws nearer, Father Tottle has recognized how a new dynamic will be added to their relationship.

“I had resolved when Mark entered formation not to interfere or comment on the formation process and leave it to those the Church entrusted it to,” he said. 

“Now that he is nearing its completion there are a growing number of experiences to be shared and I hope that he will find me a support to his ministry.”

This milestone was never his alone. Behind it were years of prayers, encouragement, and support. As DeSio continues, he does so with a grateful heart.

“Just a word of thanks to all of those who have prayed for me over the years throughout the diocese,” he said. “Ordination weekend was the fruit of 10 years of discernment and cooperation with God’s grace. I wouldn’t have been able to do it without the prayers of so many. Please continue to pray for me as I prepare to be ordained to the priesthood on May 15th, 2027!”

For more information about the Office of Vocations, click here.