In last year's Tour de France, Porte become only the second Australian ever (after Cadel Evans) to finish on the podium at world cycling's biggest event.
The Tasmanian came third behind Slovenians Tadej Pogacar (UAE Team Emirates) and Primoz Roglic (Team Jumbo-Visma).
"For me, this is a massive privilege and an honour to get this award finally," said Porte.
"It has been something I have always wanted to do, so to take it out finally, it is of great satisfaction.
"When you look at the future of Australian cycling, there are so many good riders coming through.
"So, to have my name up there now alongside cyclists like Cadel Evans, Rohan Dennis, Mat Hayman and Caroline Buchanan, it is an absolute privilege and honour, so thank you to everybody."
Porte, 36, began the 2020 season by winning the Tour Down Under then returned to Europe to continue the WorldTour season before it was postponed due to coronavirus in March.
In the Tour de France - his tenth - he overcame a two-minute deficit on the final stage to ride onto the podium, and finished off the season by placing 25th in the UCI World Championships and claiming a top-ten finish in La Flèche Wallonne.
All 2020 AusCycling Cyclist of the Year Award Winners
The "Oppy" Medal - 2020 AusCycling Cyclist of the Year
Richie Porte (TAS)
Male & Female Track Cyclist of the Year
Steph Morton (SA)
Nathan Hart (ACT), Matt Richardson (WA), Tom Cornish (NSW)
Male & Female Road Cyclist of the Year
Grace Brown (VIC)
Richie Porte (TAS)
Male & Female Mountain Biker of the Year
Rebecca McConnell (ACT)
Jack Moir (NSW)
Male & Female BMX Racing Rider of the Year
Saya Sakakibara (NSW)
Anthony Dean (SA)
Male & Female BMX Freestyle Rider of the Year
Natalya Diehm (QLD)
Brandon Loupos (NSW)
Male & Female Para-Cyclist of the Year (Road)
Meg Lemon (SA)
Stuart Jones (NSW)
Male & Female Para-Cyclist of the Year (Track)
Emily Petricola (VIC)
David Nicholas (QLD)
Male & Female ESport Cyclist of the Year
Sarah Gigante (VIC)
Freddy Ovett (VIC)