Slade is equally adept at fly-half and fullback and made an immediate impact for Canterbury in the 2008 Air New Zealand Cup. Slade scored 86 points for the side, having been thrown into the fly-half berth following an injury to Stephen Brett and Dan Carter being ruled out, as they went all the way to claim the trophy.

Slade caught the eye of Crusaders coach Todd Blackadder and he found himself included in the 2009 Super Rugby squad. Despite being played out of position on the wing, Slade made 11 starts for the Canterbury franchise. Slade went onto be selected for the Junior All Blacks for the 2009 IRB Pacific Nations Cup.

Slade was shifted to fullback for the 2009 ANZ Cup to make way for Brett at fly-half. The position shift did not deter the star in the making as he scored four tries during the tournament, including two in the final. For the 2010 Super Rugby tournament, Slade remained at fullback and once again impressed.

Slade made his debut for the All Blacks in their final match of the 2010 Tri-Nations against the Wallabies coming off the bench for Aaron Cruden in the 60th minute. Slade's love of New Zealand's domestic cup was further shown in the 2010 season as he finished second top scorer in the competition, behind Lachie Munro, despite missing games to play for the All Blacks.

Slade transferred to the Highlanders for the 2011 Super Rugby season in a bid to spend more time in his preferred fly-half spot. However, Slade had a season interrupted through injury. He missed the first five games with a broken jaw and in his third game back for the franchise broke his jaw again.

However, he returned in time to be selected ahead of Aaron Cruden and Stephen Donald as second-choice fly-half in the All Blacks squad for the Tri-Nations campaign. An impressive performance against Fiji put him in prime position to secure a place in New Zealand's 30-man World Cup squad. And Slade's wishes were confirmed when Graham Henry announced that he will go to rugby's premier tournament as Dan Carter's deputy.

Slade featured as a replacement in the opening-day win over Tonga before earning a start against Japan following Carter's withdrawal due to a back complaint. He notched 23 points against the Cherry Blossoms before being returned for the bench for the crunch clash with France, though he did feature as a replacement.

Slade was then left out of the original starting line-up for New Zealand's final pool game, against Canada, only to be handed the No.10 jersey after Carter again pulled out because of a groin problem. However, this time the injury was more serious and it was confirmed on the morning of the meeting with the Canucks that Carter's tournament was over, thus placing an enormous amount of pressure on Slade's young shoulders. He responded reasonably well, though, impressing more in play than with his goal-kicking.

Slade started the quarter-final victory over Argentina but tragically suffered a groin injury just like Carter and was ruled out of the rest of the tournament. He returned to fitness for the 2012 season and was a key figure in the Highlanders' unbeaten start to the season but his injury jinx struck again with a suspected broken ankle suffered in the defeat to the Brumbies.