He made his mark in the Victorian Football League, playing with Melbourne's VFL-affiliate Sandringham, as a tough, in-and-under midfielder, and won the Fothergill–Round Medal as the league's most outstanding young player.
Valenti made his senior debut for Melbourne in Round 8 against Adelaide in the 2008 season, he played a total of nine games for the year.
He was joint winner of the J. J. Liston Trophy in 2010, tying on 20 votes with North Ballarat's Steve Clifton.
[2] The following year, he won the Liston Trophy again, this time outright, becoming the third player in VFA/VFL history to win the award back-to-back.
With his win, there was speculation that he may be recruited by AFL teams Greater Western Sydney[3] or Essendon,[4] but neither eventuated and he remained with Port Melbourne.