“Adam can play football and we are going to adapt to how he plays and will have plenty of strike around him,” Cunningham told the St Helens Star.
“He is someone I have closely followed for two seasons.”
Walker’s previous club Hull KR were relegated in 2016, which opened up the opportunity to snap up the prop, known for his offloading ability.
“Me and his manager have had conversations about Adam’s future over that period of time,” he added.
“I had earmarked him for next season, but Hull KR’s relegation came as a shock to everybody.”