Porte rose and under the eye of Andrea Tafi on the Monsummanese Grassi Mapei amateur Italian team in 2009, finishing tenth at the 2009 Tour de Langkawi.

[12] In April, Porte went on to win the stage 4 time trial at the Tour de Romandie, finishing in tenth place overall.

[21] Porte then went on to win fifth stage time trial at the Post Danmark Rundt, in Helsingør, by a margin of 10 seconds over teammate, Gustav Larsson.

[23] In January 2012, he competed in his national championships in Buninyong and Learmonth, where he finished third in the road race,[24] and placed fifth in the time trial several days later.

[25] In February 2012, Porte took the lead of the Volta ao Algarve after winning the race's queen stage, the summit finish at the Alto do Malhão in Loulé.

[citation needed] Porte then rode the Vuelta a España in support of Chris Froome, and took second place on stage 20.

In the sixth and final stage, an individual time trial, Porte could not match Nairo Quintana over the undulating parcours, but managed to rise to second place in the general classification, ahead of Henao.

On the concluding stage eight, Froome and Porte rode clear of their rivals on the final climb, with only Andrew Talansky able to follow, to secure a one-two finish in the overall standings.

Porte lost over ten minutes and dropped out of overall contention, although Froome managed to avoid time loss by fending off several attacks from Alejandro Valverde and Quintana.

[34] On stage 18 – which finished at Alpe d'Huez – Porte's assistance proved vital for Froome, as Froome ran into difficulty towards the end of the stage; Porte dropped back to the team car to illegally get energy gels for his leader, then paced him to the end of the climb to limit his losses to Quintana and Joaquim Rodríguez.

[44] Porte then failed to finish the Vattenfall Cyclassics[45] as well as GP Ouest–France[46] which led him to end his season early after being diagnosed with pneumonia.

[49][50] Much like the previous season, Porte took victory on the queen stage of the Tour Down Under at Old Willunga Hill resulting in a second place on the overall general classification.

[51][52] Porte then returned to Europe at the Volta ao Algarve again taking victory on the queen stage to the summit finish of Malhão, this stage win succeeded in elevating Porte to fourth overall on general classification behind teammate Geraint Thomas, as well as taking the win in the mountains classification.

In the Giro d'Italia, Porte made headlines by having a motor-home to sleep in as he was the team leader while his teammates slept in hotels.

Porte initially lost 47 seconds to the peloton, but was then docked two minutes and fined 200 Swiss francs for accepting Clarke's wheel as this manoeuvre is illegal according to UCI rules, dropping him to 12th place overall.

During the final mountain stage 20, with Froome seemingly running out of steam on the long uphill finish and Nairo Quintana aggressively attacking in front, Porte was the last Sky rider to steadily pull and pace Froome up the climb, allowing him to limit his losses and secure the overall lead and yellow jersey, to gain his second Tour de France victory.

[70] Ahead of the 2016 season Porte highlighted the Tour de France and the Olympic road race and time trial as his targets for the year.

He rallied to perform well in the mountains and individual time trials, finishing fifth overall, his highest Grand Tour placing to that point.

He crashed out of the Tour de France on stage 9 while descending the Mont du Chat; he had been in an excellent position going into the high mountains being within about 30 seconds of the lead with only Dan Martin, Froome and Fabio Aru ahead of him.

Once again he was in good position prior to the high mountains being within a minute of Super-Domestique and eventual winner Geraint Thomas and overall leader Greg Van Avermaet.

He was also ahead of most other favorites including Romain Bardet, Mikel Landa, Tom Dumoulin, Froome and Nairo Quintana.

He began the 2020 season by taking the lead midway through the Tour Down Under, but then Daryl Impey took a two-second advantage going into the final stage on Old Willunga Hill.

[81] During the Tour de France, Porte found himself in a top-ten position early in the race, and by the end of the second week he was in ninth place overall.

[83] Porte recorded the third-fastest time for the stage – only beaten by Pogačar and Tom Dumoulin – and by outpacing Miguel Ángel López by nearly five minutes, he moved into third place overall.

[91] He appeared to be in good form heading into the Tour de France; however, he lost over two minutes on the opening stage, marked by several crashes.