The 31-year-old midfielder has signed a two-year deal at the Riverside Stadium after being released by Stoke at the end of the last campaign, and he revealed Boro's Leadbitter, with whom he played at Sunderland, and Potters defender Huth, who had a spell on Teesside earlier in his career, had warmly recommended the club.
Whitehead said: "I'm good friends with Grant and he loves the place. He had a good season last season and is a good professional. He does everything the right way and just wants to win.
"As for Robert, I spoke with him recently and he really enjoyed his time here and spoke very highly of the club.
"I'm old and wise enough to know what Middlesbrough is about. I spoke to the manager [Tony Mowbray], he told me what he wants and what he thinks the club can do.
"You take all that on board, but ultimately it's a football decision and I think I am in the right place."