The Greek cruised to a 6-1, 6-4 defeat of Casper Ruud on Sunday to add to title triumphs on the Riviera in 2021 and 2022.
"Getting the Holy Trinity, as I call it, is something that I will fully cherish and take the most out of this moment," he said.
"I did need a week like this a lot, especially the rough months that I have been through in the last half of 2023 until now.
"It hasn't been the best of times in terms of where I wanted to be, so getting back here and winning the title is something that I was definitely not aiming for -- it came naturally."
Tsitispas arrived in Monte Carlo ranked at 12 in the world, his worst standing since January 2019.
He had a modest 11-6 record on the year and had won just one title since the 2022 grass-court season.
"Winning this tournament three times is something I would have never imagined," said Tsitsipas.
"Even when I got it the first time, I obviously thought it was a great feeling and that place is special towards me," added the 25-year-old who had stunned Australian Open winner and world number two Jannik Sinner in the semi-finals.
"I showed some unbelievable, ruthless tennis."
Tsitsipas produced 30 winners to the 20 of Ruud who had reached the final with victory over world number one Novak Djokovic on Saturday.
He is the fifth man to win three or more Monte Carlo titles, joining Rafael Nadal (11) and Bjorn Borg, Thomas Muster and Ilie Nastase who won three apiece.
The Greek struck first with a break in the third game of the opening set, then saved three break points to lead 3-1.
'He's a dreamer'
Tsitsipas earned a double break for 4-1 and claimed the set as Ruud double-faulted after 36 minutes.
In the second set, Tsitsipas got out of trouble in a 13-minute game, saving three break points at 3-3 after leading 40-0.
He claimed the title three games later on a first match point, a forehand winner down the line.
Tsitsipas explained that his 98-minute victory was more special than his first two title triumphs and cited a no-nonsense attitude heading onto the court.
"This is amazing, I want to thank family, friends and those who made this moment possible," he said.
"(Completing) the trinity (hat-trick) is even more special than the first two."
He added: "This match was nerve-wracking - I really wanted the trinity and I got it today. I played cohesive tennis from start to finish."
Tsitsipas's father and long-time coach Apostolos insisted he never doubted his son's abilities.
"Stefanos, he's a dreamer. I could say that also he's still young in his soul, in his mind," Apostolos told atptour.com.
"As every young person they need to believe in life, they need to believe in the targets they put. That's why we are there, to remind them that they deserve to be whatever they are."
Ruud, twice a French Open runner-up, apologised to the capacity crowd for not being able to mount a consistent challenge to his Greek opponent.
"Congratulations to Stefanos for winning again, he's been playing so well all week," said 10th-ranked Ruud.
"You are now back where you belong (among the top players)."
Ruud added: "I'm sorry I could not put on a better performance today, hopefully I will be back with a better performance in another year.
"I couldn't get it this time, but hopefully I'm getting closer to these big titles.
"I want to break the barrier and win a big tournament like this."
