West End Redbacks captain Head turned his ninth score above 50 into his second Test century to top-score for his country and help Australia to a strong first-innings total of 467.
The dashing batsman, who turns 26 on Sunday, hit 12 boundaries from 234 balls in a mature knock of 114.
Patient throughout, Head spent 49 minutes and 42 balls in the 90s before he brought up three figures by driving New Zealand’s Tim Southee through backward point just after tea.
"It was about making sure I was very tight in my defence and waiting for a cut shot or one off my pads," Head said.
"It was a very refined blueprint for me today.
"Over the last couple of years as I have matured I have been able to get more hundreds. When I was younger I used to try and get through the 90s quicker than I should have. Over time you get more mature and you relax.
"I was happy to do it in ones or if I got an opportunity hit a four. I was happy to nudge my way there. I probably took a bit longer than I thought."
The Australian joint vice-captain had a Test batting average just over 40 from 25 innings heading into the Boxing Day Test.
Head’s ton was the first by a South Australian-born player at the MCG since Andrew Hilditch in achieved the feat in 1984.