Fabian Delph scored the only goal of a drab game as City claimed a 1-0 win in their play-off at the Etihad Stadium to progress 6-0 on aggregate.
At times the occasion seemed more about England goalkeeper Hart, who was recalled by manager Pep Guardiola after sitting on the bench for the first three games of season.
Hart’s future at City remains uncertain with the club poised to complete the signing of Chile international Claudio Bravo from Barcelona this week.
Fans made clear their feelings on the sudden demotion of Hart throughout, but it remains to be seen whether he still has a part to play in the Guardiola era.
If it does prove a farewell appearance, the 29-year-old was at least given a good send-off, with numerous chants, ovations and a banner underlining fans’ affections. He gave all sides of the ground the thumbs-up as he left the field.
With the tie as good as won, Hart’s recall was one of a number of changes by Guardiola, who also brought back Yaya Toure.
City rarely moved out of first gear and Steaua, who made six changes themselves, seemed uninterested. Coach Laurentiu Reghecampf had said he was resigned to defeat in the tie on the eve of the match and his indifference was reflected in the visitors’ performance.
City’s first incisive move came early in the second half when Toure slipped Delph in on goal and Cojocaru blocked. Delph made no mistake as he opened the scoring moments later by rising to meet a cross delicately chipped into the area by Navas with a powerful header.
Some bad news for City came late on as Iheanacho pulled up injured chasing the ball. Steaua defender Bogdan Mitrea initially seemed very concerned for his well-being and urged medical staff to hurry and, although the situation may not have been as urgent as that suggested, Iheanacho still left on a stretcher.
Fernandinho replaced him and guided City through the closing minutes.