Friday February 20, 2026.
Beloved husband of Susan O’Brien (nee Parks); loving son of the late Charles O’Brien and the late Dorothy O’Brien; dear step-son of Clara O’Brien; dear brother of Charlyn (the late Mick) Keane, Shannon (Rusty) O’Brien Drewing, Stephanie (Chris) O’Brien Veile and the late Brady M. and Kelty C. O’Brien; dear uncle of John Michael (Kimberly) Keane IV and Kaitlyn (Tony) Newton; dear stepfather of Angelina M. DelCortivo and the late Zackery M. DelCortivo.
Mark was a retired St. Louis City Police Officer, proudly continuing a long tradition of law enforcement service within his family.
Mark became involved in the annual Guns ‘N Hoses event in 1989. As the event’s “original voice”, he served as ring announcer until his retirement in 2024.
Outside of Guns ‘N Hoses, Mark was a legend in the billiards world, a deep passion he carried alongside his deep love for his family and his extensive circle of friends.
Services: Visitation at Kutis Affton Chapel 10151 Gravois Rd. 63123 on Thursday, March 5, 2:00-7:00 PM. Memorials to the Backstoppers appreciated.
Procession from Kutis Affton on Friday, March 6, departing at 10:15 AM for a 10:30 AM committal service in the Chapel at Resurrection Cemetery.
Susie & Charlyn, my heart breaks for you both. 💔 I pray you can find peace knowing you’ll see him again. Hugs to you both.
What a great pool player and talented announcer and an entertaining storyteller.. Mark was always my gentleman friend. Susie and Charlyn , you know we will all miss him. I met Mark when I was 16 years old. What a head of hair he had! Such a successful guy that loved life. You got to know he is at peace and for sure hanging out with Louie.
Our families will forever be intertwined you never changed. Always a great person. Super pool and foose ball player great cop love u bro
Legend, in the truest sense of the word.
I knew Mark in the late 80’s shooting pool in the old Busch Pool League. He was really good and fun to watch. I also played pool at the pool hall he co-owned in Affton. Prayers to his family. He will never be forgotten.
RIP my brother. We have been best friends since we were eight years old. We have a bond that can never be broken.
You lived a great life on your terms.
I’ll see you on the other side.
Heavenly Father,
Lord of all mercy and the Giver of every good gift,
On this day, Friday, February 20, 2026, we lift up to You the life and legacy of Your servant, Mark Conaway O’Brien.
Thank You for calling him home after 70 years of faithful service—first as a devoted St. Louis City Police Officer who proudly carried on his family’s long tradition of law enforcement, then as the beloved “original voice” and ring announcer of the Guns ‘N Hoses charity event from 1989 until his retirement in 2024. Thank You for the joy he brought to arenas and pool halls alike, where his skill, laughter, and larger-than-life presence made him a true legend in the billiards world.
We praise You for the man he was at home: the beloved husband of Susan (née Parks), the loving son of Charles and Dorothy O’Brien and dear step-son of Clara, the cherished brother to Charlyn, Shannon, and Stephanie, the proud uncle to John Michael and Kaitlyn, and the devoted stepfather to Angelina. We entrust to Your tender care the memory of those who have already gone before him—his parents, brother Brady, sister Kelty, and stepson Zackery—and ask that You surround Susan and the entire family with the same comfort and strength Mark so freely gave to others.
Lord Jesus, who walked with the weary and welcomed the faithful home, receive Mark into the eternal rest You have prepared for those who love You. Wipe every tear from the eyes of those who mourn him. Fill the empty chair at the family table, the announcer’s seat at ringside, and the corner pocket of every favorite pool hall with Your abiding presence.
May Mark’s example continue to inspire every officer who puts on the badge, every friend who raises a cue, and every family member who carries his name. Let his deep love for You, for Susan, for his family, and for his city be a living testimony that points others to the Savior he served.
Grant us all the grace to live with the same courage, humor, loyalty, and faith that marked Mark’s days, so that when our own earthly shift ends, we may hear the words we long to hear:
“Well done, good and faithful servant… Enter into the joy of your Master.”
In the strong name of Jesus Christ, our risen Lord and the Good Shepherd of every police officer, every family, and every soul, we pray.
**Amen.**
May the Lord bless and keep Susan and the entire O’Brien family in the days ahead, and may Mark rest in perfect peace until that glorious resurrection morning.
Thank you for such a beautiful post. God Bless you & your family…Susan Sorrentino Hill
You were always one of my favorite nephews. I always loved hearing your long funny stories. You always knew the right thing to say in any situation. You will be so missed but I’ll see you again one day. Rest in peace Sweet Mark.
Rest in Peace, Mark.
You were a great husband to my dear friend Susan and you will be sorely missed.
God Bless you Susan, you are in my heart and prayers.
Jeanie Goetz
Mark
May the road rise up to meet you.
May the wind be always at your back.
May the sun shine warm upon your face;
the rains fall soft upon your fields and until we meet again,
may God hold you in the palm of His hand.
Mark made a well known arrest of a rapist in Forest Park that generated national news and brought great credit to the St. Louis Police Dept. When Mark rejoined the police department after a lengthy absence he was an inspiration to us old timers by staying in shape and excelled passing the fitness challenge.
As a supervisor in the 1st District I was proud to serve with Mark, who brought an experienced hand to the young officers around him.
Rest in peace my best friend since 3 grade. Partner in ride the rail. & Sports Center. The will never be another Mark the Shark OBRIEN Mark & I have a lot great memories that no one can match that we had. The only other person. Steve Holly.
So sorry to hear the sad news of Mark O’Brien’s passing I first met Mark at OK corral pool hall when I was a little kid I liked him right away. We would talk about sports baseball boxing and politics. He was a walking encyclopedia. I’ll never forget going to His pool hall on telegraph Road he was always eating steak ‘n Shake hamburgers I used to sit there and listen to him and the rest of the pool sharks that would come to town and make deals never laughed so hard in my life. They were all great characters and their own way I Miss that I Was quite a bit younger than Mark, but I always liked listening to him and getting his take on Things he was kind of like the big brother I never had i’ll always remember him!! Goodbye for now great patriot🫡🇺🇸 Michael M
My thoughts and prayers are with Mark’s family and many friends. He was a good guy🙏
What a wonderful soul !!!
Mike & I send are deepest sympathies to your family Susie. We have known Mark and all your families most of our lives! Mark was a great friend & brother we loved him and all he accomplished here! I am sure he has all his family around him in Heaven – May God Bless his sweet loving soul eternally!
My thoughts and prayers are with you and your family. God bless you!