Villa fractured his left leg at the Club World Cup in December and the 30-year-old, Spain's all-time leading scorer, was finally given the all-clear by Barca's medical staff at the end of last month.
He came on in the 73rd minute of Barca's 2-0 win against Dinamo in the Romanian capital and said he had "felt very good on the pitch" and was "very pleased" with his return.
"My aim is not to be the player I was before, I want to be better," he told reporters. "We have to be patient, I have been out for a long time, more than I expected.
"What I want now is to focus on the present and the future and forget the past. My job is to improve day by day."
Barca, whose three-year run as Spanish champions was ended by arch rivals Real Madrid last season, play their opening La Liga match of the 2012-13 campaign at home to Real Sociedad on Sunday August 19.