Pearson, who has been appointed to the role of executive director, previously held the position of commercial director at Elland Road before going on to purchase Hull City in 2001.
He sold Hull in 2007 and soon took up the role of executive chairman at Derby County, before returning to Humberside within just two years as he resumed the position of chairman at the KC Stadium.
In 2011 he then purchased Super League side Hull FC, which he still owns, and eventually moved on from the Tigers the following year.
His most recent role in football was a short lived one at Sheffield Wednesday as part of their sporting committee.
"I'm here to assist Massimo as much as possible on all sides of the club and I’m really looking forward to it," said Pearson.
"I'll be like his right-hand man as executive director at the club, trying to get the club moving forward in the right lines and in tune with its supporters.
United chairman Massimo Cellino added: "Adam is coming here to be my right-hand man, to help me with everything that needs to be done. There is a lot of work to do.
"He is a good man. He loves football and he knows this club well, that is important.
"Since I came back to Leeds, I have not stopped working, but Adam will help me now. I wanted him here at Leeds and I believe the working relationship will be positive.
"He has quickly started in his job and he has shown in the past that he knows how to be successful in football.
"We will work together on making sure we are ready to have a strong season on and off the pitch."