The linebacker out of the University of Southern California was the last of the Texans eight draft picks to sign, after the team signed second rounder DE Connor Barwin on Friday.
Cushing was the 15th overall selection in this year's NFL Draft and he will help bolster a Texans defense that ranked 22nd in total defense in 2008. He started all four years at USC and was a finalist for the Butkus Award in 2008.
Texans head coach Gary Kubiak says Cushing will arrive in time for Saturday's afternoon practice.
"It's important. Like I said yesterday, it's not like he's missed anything he wasn't doing during the course of the summer, but his teammates are two practices ahead of him and a long, long day ahead of him. He needs to be here and be a part of it and catch up," said Kubiak.
Texans owner Bob McNair was equally pleased that Cushing's deal was completed early in camp.
"You're dealing with a lot of different people and lot of things beyond your control. They've been down here late in the evening, early in the morning working on it. So I'm real pleased that we're going to have him in here," said McNair.
The signing leaves only holdout CB Dunta Robinson as the last Texans player not in camp. Robinson was slapped with the franchise tag and is unhappy on not receiving a long-term deal.