In 2008 Rockliff, a medium-sized, smart and creative forward, was the leading goalkicker in the TAC Cup with 59 goals and won the Murray Bushrangers' Best and Fairest award, but was overlooked in the main draft. He was, however, drafted by the Brisbane Lions with the fifth selection in the 2008 Pre-Season Draft. He is now known as one of the greatest draft steals in recent AFL history
Rockliff forced his way back into the senior Brisbane Lions side in Round 3, 2010 where he has since featured predominantly in the midfield rotation. He received an AFL Rising Star nomination in Round 13, 2010 and despite being heavily favoured to win the award, finished third behind winner Daniel Hannebery and Tom Scully in the end of year voting.
After an incredible season with the Lions, who finished 15th on the ladder after only managing four wins, Rockliff ended the season averaging 27.7 disposals, 5.6 marks and 5.4 tackles per game. Rockliff was rewarded by winning the club's best and fairest award over favourite Simon Black, who also had a strong season.
In 2014 Rockliff established himself as one of the elite midfielders of the competition, averaging a league-high 32.7 disposals and 9.1 tackles a game and recording 40 or more disposals five times. In Round 18 in the Q-Clash against Gold Coast, Rockliff gathered a career high 47 Disposals (31 kicks and 16 handballs) as well as 10 tackles. Rockliff was awarded his second Merrett-Murray Medal as Brisbane's best and fairest player.Rockliff was also selected in the 2014 All-Australian Team on the Interchange after his remarkable season that was recognised.