The 47-year-old signed a three-and-a-half year contract at the City Ground on Friday night after a compensation package had been agreed with his former club Portsmouth. Clark himself only took over as chairman on Wednesday after Nigel Doughty took the decision to stand down at the same time as outgoing boss Steve McClaren, albeit remaining as owner.
He told the club's official website: "I'm really excited about the appointment. Steve was always at the top of the list and he fits the criteria that we set out when I first started looking at this with the board last week. He's enthusiastic, he's hungry, he's got a terrific CV and he's experienced at this level. He was everything we were looking for."
Clark added: "Experience of the Championship wasn't the most important thing - the most important thing was his CV. For me it's all about the CV and not the job interview because that tells you what he's already done and not what he might do in the future.
"There's no certainty in any appointment but looking at Steve's CV we're really pleased to have got him."
Cotterill travelled to the east midlands on Friday afternoon as details of the agreement with Portsmouth, which are understood to include a package in the region of £250,000 for Pompey, were finalised, and he has vowed to embrace the club's "great tradition".
"I'm very excited - it's a wonderful football club which has great traditions which should be embraced,'' he said. "I'm really looking forward to getting to work on the training pitch with the players.
"I'm passionate, I want us to play good football and play on the front foot. I think there are some very talented players in the dressing room and we'll be looking to enhance that and do well with them. I like to think of myself as hard working, honest and a winner."
Cotterill admitted he left Fratton Park with a heavy heart, though.
"It was a wrench to leave Portsmouth after everything we've been through together there but I'll remain great friends with people down there," he added.