Jelbart was educated at Scotch College, Melbourne where he took up rowing.[2] His senior rowing was from the Australian National University Boat Club, the Melbourne University Boat Club and later Monash University.
He was a founding member of the Australian National University Boat Club when rowing commenced at that institution in 1964. He was the ANU's inaugural sculling representative at the 1966 Intervarsity Championships[3] and raced again in that event at the 1967 Australian Intervarsity Championships placing second to Sydney University's Dick Reddel.[4]
Jelbart made a move to the Melbourne University Boat Club in 1967. He raced in their colours at the 1968 Australian Rowing Championships contesting the coxless pair national title.[5] He rowed in MUBC coxed fours contesting national title events at the Australian Rowing Championships in 1970, 1974, 1976 and 1977;[6] coxless fours in 1970 and 1978;[7] and in a Victorian eight in 1970 which contested an open men's eight title.[8]
Jelbart first made state selection for Victoria in the senior men's eight of 1968 contesting the King's Cup at the Interstate Regatta within the Australian Rowing Championships.[9] He rowed in ten Victorian King's Cup eights from 1968 to 1978 (excluding 1974) and was victorious in 1968, 1970 and 1971 (at stroke).[2]