"The man wasn't my father — I haven't really had a chance to meet him — but someone mum was with while I was quite young. There were a lot of bad times, but there's one night in particular that has always stayed with me.
"This person hit mum right in front of me. She was so close to where I was standing I could've reached out and touched her. She fell to the ground and he pulled her around the lounge room by her hair, threw her into a room and slammed the door shut. I can still remember her screams.
"He was ripping the place up. It was like a home invasion, but the crime was being committed by someone who lived with us. The walls were getting smashed, doors were broken, glasses were being thrown around and broken all over the kitchen.
"It was an awful night. There were a few like that.
"I had so much anger and frustration in me. I was only little, but it still killed me that I couldn't step in and stop this person from hurting my mum."
Lewis is grateful for the help and support of his former primary school principal, at Doonside Public School, which helped him navigate the tough period in his childhood.
His mother continued to suffer at the hands of her ex-partner for years, before the relationship eventually ended.
During those dark times however, Lewis revealed he was too scared to sleep over at his friends' houses, as he was worried about what might happen to his mum and sister in his absence.
The hardship he endured as a child came before more challenging episodes later in life, including suffering serious injuries, and his two-year fight to overcome thyroid cancer before returning to play State of Origin for New South Wales.
Speaking on a podcast with NRL.com, Lewis explained he hopes by sharing his own painful stories he might be able to offer hope to others in similarly grim situations.
"Talking about the domestic violence stuff was pretty tough. Purely because it brings back so many memories," he said.
In a glittering career that saw him also go on to play 16 tests for Australia, Lewis also experienced plenty of good times, which both he and his mother and both proud of.
"I had a chat to her the other day and she got to sit down and read the book and she was crying. I said, 'What are you crying for'?," Lewis said.
"And she said, 'It just brings back so many good memories."