Breaking down in tears, Morrissey said the past week since her tragic death in a road accident had been the worst of his life.
Peggy Morrissey (94), was laid to rest this afternoon Mullagh, Co Clare, following her death last Tuesday morning.
Neighbours, friends and colleagues of the sports broadcaster attended the funeral at St Mary's Church in Mullagh, where Peggy was a much-loved community member.
Originally from Mallow in Co Cork, Peggy was predeceased by her husband Marty Snr in December 2004.
A family photo, Peggy's rosary beads and prayer book, her red lipstick, her driver's licence, a Cork flag as well as the Statue of Liberty were among the items placed in front of the altar as symbols of her life.
Addressing mourners Morrissey said it was his honour to be Peggy's son and only child.
He described her as "a rebel, a proud woman from North Cork who loved human contact and thrived on conversation and craic and banter.
"She was loyal, determined, witty, funny, deeply religious, a daily mass-goer, so loving - a fabulous wife and adoring mother.
"She was also a 5ft 4in force of nature - argumentative, stubborn, fiercely independent, intensely confident and to be honest really annoying on occasion.
"This was Peggy Morrissey. In my humble opinion, the greatest Irish mother in the history of motherhood."
He paid tribute to his mother's deep faith. Morrissey said he was "so sorry in so many ways she is dead" because she would be so excited to see the five priests and the bishop who turned out for her funeral.
He thanked his two friends and Peggy's favourite musicians, Sharon Shannon and Tommy Fleming, who performed at the funeral.
Retired RTÉ journalist Tommie Gorman, as well as representatives from President Michael D Higgins and Taoiseach Micheál Martin were in attendance.
Morrissey described Peggy as an extraordinary woman, and together as mother and son, they were a dynamic duo.
"Next Saturday, my dad will be dead 17 years. Peggy lived alone along the wild Atlantic Way. She was lonely, she was heartbroken at times.
"She rang me every morning or I her at 10 o'clock. Then again at lunchtime, after 4 pm and when the
Six One news was over; then at 10 pm and again when she was in bed."
His voice breaking, Morrissey said softly: "My mother was no ordinary woman. How am I going to survive without her?"
Morrissey recalled Peggy's intense dislike of growing older. He reflected fondly on when she refused to give her date of birth while renewing her driving licence.
"She hated the wordage. Depending on what day of the week it was, Peggy could tell you she was 78, 84, 88.
"Mom had no filter, she could say anything. Her timing sometimes left a lot to be desired.
"When she wanted me, she wanted me now."
The Morrisseys lived for many years in New York but returned to Ireland and bought a pub in Marty's father's hometown in Clare when Marty was 10-years-old.
Morrissey recalled how Peggy would deal with rowdy customers rather than his dad.
"In the pub, she was known as Mrs Morrissey, and if someone misbehaved, my father was way too soft.
"So it was left to Peggy to jump into action. For my mother, there was no yellow card, no black card or sin bin - it was always a straight red.
"She had two fears. She hated the thought that she could one day end up in a home for some reason.”
His voice breaking, Morrissey said: "I would never, ever have allowed that happen to her."
"And she hated wind and storms with a passion.
"She was a rogue, as you here will have known. She always put on a seatbelt when she was in my car, whether we would be driving to Spanish Point or up to Knock.
"I learned over the last few days that she didn't wear her seatbelt when she was driving herself."
Morrissey said since he lost his mother, he had been looking for a sign that she was safe and happy.
"Yesterday, after bringing Mom to church here and Fr Donoghue started praying, something unusual happened.
"A beautiful butterfly flew around the altar and over her coffin, only to be joined a few moments later by a second butterfly, and they flew together over the short aisle over the seat where she always sat in this church.
"I have to ask what are two butterflies doing in a church in Mullagh in December.
"Maybe I'm losing it, but I want to take it as a sign that my Mom and Dad are together again, and they are happy.
"What were the chances an only child from west Clare would meet and fall in love with an only child from north Cork and have an only child. No aunts, uncles or first cousins.
"Where once there was three of us, sadly now there are one."
Addressing his mother directly, Morrissey said: "But I am lucky mam, I have three families and by God did they love me this week.
"My friends here in this parish are my brothers and sisters who have responded so magnificently to my greatest tragedy of losing you last Monday night.
"I'm lucky, Mam and Dad, you brought me home to this parish when I was 10. This is where I belong, this is home."
Paying tribute to his colleagues in RTÉ, Morrissey said they were like family to him, "and their support I will cherish for the rest of my life.
"It's hard to comprehend what my colleagues did over the past few days, but my respect for the organisation and its people reached new heights. I know many of them are here today.
"My third family is the GAA community nationwide. I am overwhelmed by the people from Croke Park to every county in Ireland who has reached out to me in my hour of need.
"I thank you from the bottom of my heart, everyone who rallied around me because, to be honest, I was good for nothing."
Morrissey paid a special tribute to emergency services.
"I want to think the gardaí, fire brigade and ambulance who did their best to help my mother in last few moments.
"I asked them when they took mom out of the car that they say three Hail Marys and they did.”
Morrissey said his mother taught him to be honest and fair and to stay grounded.
"She often told me, especially after a row, that she adored the ground I walked on.
"I loved my mother with all my heart. I spent all my life with her. She gave me everything - total and utter unconditional love.
"I will miss her so much. My life has changed this week.
"Mom, I adored the ground you walked on. My life revolved around you, and I would do it all again if I could.
"We were a team: the most formidable mother and son team in the world.
"I have to let you go now, mom. Go to dad and tell him I loved him too.
"You lived life to the full. There is no doubt, Peggy Morrissey, you did it your way.
"Mum, thank you for giving me the strength to do this. I love you."