He added that it seemed like everyone "was working for the same goal."
Perzel and nine other people were originally charged in the case, known as Computergate, in which state prosecutors allege that members of the House GOP caucus used taxpayer funds to buy expensive computer programs to aid their reelection efforts. Perzel and five other defendants have pleaded guilty.
McClintock is among them, having pleaded guilty last month to one count of criminal conspiracy.
He said Tuesday that it took him years to admit to his family and to himself that he had done something wrong.
"You go through a tremendous state of denial," McClintock testified. "I finally came to the realization that I actually did this. . . . It was the hardest decision for me to make."
Three people remain at the defense table: Brian Preski, Perzel's former chief of staff; former State Rep. Brett Feese; and Feese aide Jill Seaman.
McClintock testified that Preski, in addition to being Perzel's chief of staff, worked on the once-powerful Northeast Philadelphia legislator's reelection campaigns. He said that Preski was paid by Perzel's campaign fund for election work.
On cross-examination by Preski's attorney, Bill Winning, McClintock said it was not uncommon for Preski to put in 70- or 80-hour workweeks in the Capitol.
McClintock said that Preski had "a lot of responsibility" in his government job, and that he did not believe Preski's campaign duties interfered with that work.
Under questioning by Winning, McClintock also acknowleged that he did not remember Preski's ever directing him to call House GOP caucus-paid technology staff for campaign-related work.
Testimony in the case is expected to resume Monday.
Contact staff writer Angela Couloumbis at 717-787-5934, firstname.lastname@example.org or @AngelasInk on Twitter.
This article contains information from the Associated Press.