My father won first prize in a photo contest and was elated.
Literal
Father [topic-は] photo contest [in-で] first-prize [object-を] won [then-し] triumphant was.
意気揚々 is a four-character compound meaning 'triumphant, in high spirits.' 一等賞を獲得する (to win first prize) is formal. し connects the winning to the emotional state.