Prop Jackson, 32, has signed a one–year deal while 22-year-old Massey has extended his stay with Cas under a two-year contract.
"I'm really pleased to be going round again - I'm really enjoying myself at Cas,” Jackson told the club’s official website.
"I feel that I can still do it physically and I'm enjoying my rugby as much as ever. There's a good bunch of lads here and hopefully we can finish this season on a high and improve again next season."
Massey, who came through the ranks at Castleford, has racked up 11 appearances for the Tigers this season.
"I'm happy to be staying at Cas - I've come through the system here and I never really wanted to go anywhere else," Massey said.
"There's a really good platform here for the new coach to build on and I'm glad to be a part of the club's future.”
Castleford take on Wakefield in a Super League match on Saturday.