It was confirmed last week that Senior would be leaving Leeds at the end of the season, but he has been given the opportunity to maintain his record of playing in every season of Super League at the Racecourse Ground.
He said: “I am delighted to accept the Crusaders offer of a two year deal.
“After the heart wrenching decision to leave Leeds after 13 years it was very important for me to find the right club.
“I was fortunate to receive several offers from Super League clubs but after speaking to Iestyn I was particularly impressed with his plans and enthusiasm for the future of the Crusaders.
“I am aware that the club has a difficult building process ahead and I feel that with my 18 years of professional rugby experience I will be able to contribute greatly and hopefully help change the Crusaders into a club which is challenging for honours.
“I see this move as a great challenge and I hope that the drive and determination that I have to succeed will bring success to the Crusaders.
“The last few weeks have been difficult for me with my injury and I am not a good spectator. My knee is on the mend and I am relishing the opportunity of getting back on the field next season after this break fresher than ever.”
Senior is the highest try scorer in Super League history with 199, and was the first man to reach 500 appearances in the competition.
“He has been the top centre in Super League for over 12 years now and players of Keith’s quality do not come along very often.
“I’ve played alongside Keith and he is a very special player. He’s a devastating attacker who always gives 100% to the cause. Keith’s leadership skills, experience and winning mentality can only make us a stronger team next season.
“Keith will offer us size and power, as well as a try-scoring threat. He is still at the top of his game and his signing is a major coup for us.
“I spoke at great length with Keith before he signed. He’s still got a drive and a hunger to succeed and he has bought in to what we are trying to achieve here in Wrexham.
“It is an exciting signing for us and I am looking forward to working with him.”