The deputy prime minister said he chose to "talk to normal people" in Cornwall.
He told LBC he was not "sheepish or ashamed" of what Chancellor George Osborne announced.
The statement included an Â£800m reform of stamp duty and was followed by warnings of deep spending cuts in the next parliament.
Speaking on his weekly radio phone-on, Mr Clegg was faced with a recorded call from shadow chancellor Ed Balls, who said that "just by not showing up" the deputy prime minister could not hide his party's support for coalition government policies.
"I had a choice," replied the Lib Dem leader.
"I have been doing these Autumn Statements and Budget statements for five years now, and sitting dutifully there."
He said everything in the statement was there because the Lib Dems had agreed to it, saying the stamp duty changes, which will abolish the current "cliff edge" mechanism, was "something we have been banging on about for years now".
"I am not sheepish or ashamed, far from it," he said.
"I am proud... we own it, I co-authored it."
In the aftermath of the statement, it emerged Lib Dem Business Secretary Vince Cable had written to the Office for Budget Responsibility, asking for a distinction to be drawn between agreed coalition spending and future years' projections.
Mr Clegg said reports of a difference of opinion between Mr Cable and Lib Dem Chief Secretary to the Treasury Danny Alexander were "complete nonsense", adding: "We proudly stand together in this coalition government to sort out the mess created by Ed Balls".
Lib Dem leader Nick Clegg says he is "proud" of the government's Autumn Statement, despite not turning up to the Commons to hear it delivered.