Leeds Tykes have returned to the Premiership following a one-year absence after winning promotion from National League One.
Having beaten Otley 40-12, the Tykes' promotion was confirmed when Earth Titans lost to Doncaster, to fall 10 points behind with two games left.
"I am proud of everyone associated with the club for their efforts," said coach Stuart Lancaster.
"I've been here since 1992. This is one of the best achievements ever."
Lancaster said he did not foresee substantial changes to the playing staff for next season.
"I am confident in the ability of our squad to be more than competitive in the Premiership," he said.
"Anyone who comes in will fit into the culture of our club."