He faces a minimum of probation and a maximum sentence of five years in prison and a $10,000 fine.
Bowman said nothing in response to reporters' questions as he briskly left the courtroom after the proceeding, accompanied by his attorney.
He was among 10 people charged by prosecutors from the state Attorney General's Office in 2009 in an alleged scheme of spending taxpayer money to buy sophisticated computer programs that ended up being used for political campaigns.
Five others have already pleaded guilty in the case. That number includes former House Speaker John M. Perzel (R., Phila.), who is expected to testify during the trial. Opening arguments are scheduled for Monday morning.
Frank Fina, lead prosecutor in the case, said Bowman was the first of the 10 defendants to begin cooperating.
"Mr. Bowman cooperated immediately after he was charged," said Fina.
With Bowman's plea, three people will now be seated at the defendants' table - including Brian Preski, Perzel's former chief of staff, Feese, and another ex-staffer to Feese, Jill Seaman. Another defendant who was originally part of the 10 charged will be prosecuted separately this year.
"Computergate" grew out of the attorney general's wide-ranging Bonusgate investigation, which charged House Democratic caucus members with using taxpayer-funded bonuses to award staffers for campaign work. Perzel and others from the House Republican caucus had been charged with conspiracy, obstruction of justice, and conflict of interest.
A grand jury found that Perzel had spent upward of $10 million in taxpayer funds to create as many as a dozen computer programs designed to give him and other GOP politicians an edge in elections.
Last month, Samuel "Buzz" Stokes of Philadelphia, Perzel's brother-in-law and former campaign manager; Eric Ruth, Perzel's nephew and a former House Republican technology employee; former campaign aide Don McClintock of Voorhees; and Paul Towhey of Blue Bell all pleaded guilty in the case.
Contact staff writer Angela Couloumbis at 717-787-5934, firstname.lastname@example.org, or @AngelasInk on Twitter.