The 35-year-old has been recognised in the Queen's Birthday Honours List for his charitable work away from the football field.
Defoe developed a strong friendship with Lowery while the young Sunderland supporter battled neuroblastoma - a battle he sadly lost just under a year ago.
After launching the Jermain Defoe Foundation in 2010 following a hurricane in St Lucia, the birthplace of his grandparents, the 35-year-old says that he feels both pride and sadness due to the timing of his OBE.
"It's obviously mixed emotions because obviously standing here [is] one of the proudest moments of my life, but at the same time remembering all the hurt," he said.
"I've got great memories of Bradley in my head but it wasn't easy seeing someone that you love suffer like that, especially a young kid, where he didn't really understand what was going on and you have to remain positive."
Liverpool legend Kenny Dalglish was the highest-profile sporting figure to receive a knighthood in the list for 2018.