Pickersgill, 27, is one of the Vikings’ longest serving players having first joined in 2009, initially on loan, from Warrington, while Joseph joined the club in the off season from Bradford.
The pair are now tied to the club until the end of the 2015 season.
Head Coach Denis Betts said: “These signings show the stability we are trying to add within our squad.
“Steve Pickersgill has proved his worth to the team on a number of occasions and for a while he’s just been on one year deals at the club. I believe the timing is now right to give him some stability and help him to advance his career further. He has come on leaps and bounds over the past few years which is a real credit to how hard he works, and it was my pleasure to offer him a deal.
“Phil adds both value and also ‘something different’ to our first team squad, and the exciting thing is there’s so much more still to come, hence the reason for offering him a contract for another couple of years.”
Joseph, 28, has previously played for Huddersfield, Swinton, Hull KR, Halifax and Oldham, before going to Bradford, initially on trial, to earn a full-time deal.