O’Connor, Daniel F., of Medford, formerly of Cambridge, passed peacefully at home surrounded by his loving family on April 3, 2021. Beloved father of Bridget O’Connor of Medford, Tim O’Connor and his wife Alice of Medfield, and Eileen O’Connor of Peabody. Enormously proud ‘Papa’ of Meghan, Kaitlyn, and Danny. Survived by his longtime devoted partner Judi Hayden of Medford. Dear brother of Helen Taylor of Somerville, Tom O’Connor of Salem, NH and the late Mary Duffy, Eileen Perry, Catherine ‘Renie’ Mazzeo, Elizabeth ‘Betty’ MacNeil and Jack, Bobby and Timmy O’Connor. Dan is also survived by Shirley O’Connor, and many nieces and nephews, relatives and close friends. Retired Lieutenant Cambridge Fire Department. Late U.S. Marine Corps Veteran. Visiting Hours will be held on Thursday from 4-7pm in St. John’s Church, 2254 Mass Ave., in North Cambridge. All attendees are required to wear face coverings, practice social distancing, kindly enter through the Mass Ave. doors, pay their respects and exit the side doors to allow other guests to enter. His Funeral Mass will be held at St. John’s on Friday at 11am. Relatives and friends are invited. Burial and Military Honors will follow in Oak Grove Cemetery Medford. In lieu of flowers, gifts in Dan’s memory can be made to Lahey Hospital & Medical Center – Advanced Heart Failure Clinic, 41 Mall Road, Burlington, MA 01805. To send an online condolence, visit www.keefefuneralhome.com