John Dennis Leonard

Loving and devoted husband, brother, father & grandfather, John Dennis Leonard Sr., 82, passed away peacefully at home on January 27th, 2026 surrounded by his family. John was a long time resident of Arlington Heights, raising his three children and then enjoying his retirement years joyfully surrounded by his grandchildren. Always quick to make a joke, his warm, easy going nature made him loved by many.

John was born in Chicago to the late John Edward and Eleanor Catherine (Devers) Leonard on October 19th, 1943. Growing up in Villa Park, John attended St. Alexander Grade School where he met partners in crime, Jim Meenan and Tom Riggs. The inseparable trio were often known to cause mischief for the nuns. He then attended St. Mel’s High School in Chicago, graduating in 1961 with an award for Perfect Attendance and Punctuality for Four Years. This remained a hallmark of his character throughout his life. He went on to earn a Bachelor of Science in Business Administration in 1965 from Creighton University, Nebraska. He was a proud member of the Alpha Kappa Psi business fraternity on campus and proudly passed the torch to his granddaughter who followed his footsteps and joined the fraternity at her university. After graduating from Creighton, he took a position as an auditor at Walgreens. John went on to have an illustrious 40 year career with Walgreens leading audit and inventory teams and ending his journey running the loss prevention department. Ever the athlete and scholar, he participated in baseball leagues, bowling leagues and even formed a “trivia lunch group.” Because of his curious nature, especially regarding ever changing technologies, he continually took classes at Harper College throughout his life.

When his best friend, Jim, started dating Clare Hunnewinkel in college, the two of them set him up with Clare’s younger sister Kathy. The stars aligned a year later when John returned home from college and they started dating. John and Kathy celebrated their marriage at St. Alexander’s Catholic Church, on October 22, 1966. They welcomed their first daughter Caroline in the fall of 1967, their son John Jr. the following year, and their second daughter Kimberly in 1973. John’s family was his pride and joy! He was a true family man. He loved nothing more than spending time with his wife and children and prioritized building a life together in the community. He forewent several career opportunities, his ultimate sacrifice ensuring his children were not uprooted.

John was a mentor to children throughout his life, coaching multiple little league teams right out of college and continuing on through to his own children’s teams. John was very proud of the fact he coached Dan Schatzeder in little league and brought that team to the state championship. Dan went on to play in the major leagues and ultimately a member of the 1987 World Series winning Minnesota Twins. John enjoyed following his career and looked forward to going to see him play every time he was in town.

John was best known for his “Dad Jokes” and his infectious smile, bright blue eyes, and playful personality warmed every room he entered and brightened everyone’s day. He enjoyed dancing and his children have fond memories of him practicing his disco moves with Kathy around the house. The family grew with the additions of spouses and he welcomed and loved each one as one of his own children. And the grandchildren that followed were his greatest joy! He definitely was made to be a grandpa, and he loved nothing more than spending time with them, showing them off around the neighborhood or bragging about them to friends and strangers alike, and he continued to attend as many of their games, ceremonies and graduations as possible.

Living in Arlington Heights, John took an interest in horse racing at the Arlington Race Course and for many years had an annual pass. He meticulously tracked horses & jockeys at Arlington and other racecourses across the country. He kept a log of all his bets, winnings and losses. He never won the big one, but was proud of the fact that he had an overall winning record. Later in life, John discovered his love of theater, participating in multiple community theater productions, where he was able to express his boundless humor, and love of dancing. Being from Chicago, he loved following the Cubs, Bulls and Bears as well as any team from Creighton. You could often find him jogging or walking the neighborhood in his favorite Cubs or Creighton gear. John was a true Jesuit, he quietly lived and modeled his faith in his everyday life. He generously gave of his time and talents, serving on the church Finance Committee, hosted Baptism classes for expecting families, and led the fundraising committee for the St. Thomas of Villanova Las Vegas night for many years.

John is survived by his loving wife, Kathleen Marie (Hunnewinkel) Leonard, his children Caroline (Steven) Bachert, John (Sheryl) Leonard and Kimberly (Kurt) Seger, his siblings Rita (Harold) Johnson, James (Patricia) Leonard, and Jerome (Marlene) Leonard, his grandchildren Brian, Lauren, Kathleen, Emily and Thomas Bachert, and Maya and Charlie Seger, and many nieces, nephews, extended family members and friends.

Visitation will be held on Monday, February 2nd, 2026 at 9:00am until the time of the Mass at 10:00am at St. James Parish, 820 N. Arlington Heights Road, Arlington Heights, IL 60004. In lieu of flowers, memorial contributions can be made in John's memory to Creighton University’s Heider College of Business Scholarships.