Speaking today at a ceremony marking workers day, Rouhani congratulated voters for "choosing the best" in both Friday's runoff elections and the original vote in February.
The bloc fell three seats short of a majority in the 290-seat legislature, but emerged with the largest parliamentary faction with 143 seats. Hard-liners secured 86 seats and independents won 61.
The moderate-reformist camp supports Rouhani and backs the nuclear deal signed last year with world powers. Their parliamentary successes could boost Rouhani's own chances in presidential elections scheduled for next year.