"I give them credit. They attacked from all angles," Watt said during his introductory press conference Tuesday, according to Josh Weinfuss of ESPN. "Their recruiting pitch was strong and heavy."
Watt said he texted Murray after choosing Arizona, praising the star signal-caller: "I'm here because I believe in you."
"You have to have a quarterback to have a chance. He's our guy and I'm looking forward to it," he added, per SportsRadio 610.
The future Hall of Famer reunites with a handful of familiar faces, including defensive coordinator Vance Joseph, who was on the Houston Texans' coaching staff during Watt's first three NFL seasons.
"I had a great time with Vance early in my career," Watt said. "That had its own merits, and his scheme, I'm excited to play in again."
Watt will also rejoin former Texans co-star DeAndre Hopkins, who was traded to the Cardinals last year.
"It doesn't hurt to have one of the greatest receivers stumping for you," he said.
Watt agreed to a two-year deal reportedly worth $31 million with the Cardinals on Monday after parting ways with Houston in February.
The 31-year-old, who's racked up 101 career sacks, will wear No. 99 with the Cardinals. The jersey was previously retired for former halfback Marshall Goldberg, but Goldberg's daughter has given Watt permission to wear it.