Age 84, of South Fayette Twp, on April 15, 2022. Beloved husband of the late Maccalleen “Babe” (Castelli) Desmet; loving father of Lenny (Lisa) Desmet, Lionel (Maureen) Desmet, and Danneen “Dee” (Gary) Desmet Cellone; cherished grandfather of Alisha, LaCole, LaSalle, Candace, LaKayla, Brandon, Bree and Chanel and great-grandfather of Brayden, Lainee, Miley, Zyler, Conner, Maddox, and Rocco; brother of Jane (Ted) Mitchell, Florine (Paul) Rolin, Sandra Desmet, and Alan (Harriett) Desmet. Leonard was the owner and operator of Desmet Contracting and a Veteran of the U.S. Army. He was a past South Fayette Commissioner and a member of the Bridgeville American Legion. All arrangements are private and entrusted to the Warchol Funeral Home Inc. 3060 Washington Pike, Bridgeville (412.221.3333). Memorials may be made to the Chron’s and Colitis Foundation, 6425 Living Place, Suite 200, Pittsburgh, PA 15206.