Hæstad played for the youth teams of Randesund IL and Vigør. He was signed by Start in 2001, and debuted in the Norwegian Premier League in 2002, when the youthful Start squad only made 11 points and were relegated.
After two seasons in the First Division, Start were once again promoted in 2004, with Hæstad as one of the team’s central players. Hæstad has continued in great form after the promotion, and was named player of the month by NRK in April 2005. In May the same year, he debuted for the national team in a private match against Costa Rica, to great acclaim.
In July 2006, Hæstad launched a music single This Is For Real together with four other professional Norwegian footballers - Morten Gamst Pedersen, Freddy dos Santos, Raymond Kvisvik, and Øyvind Svenning. They call their band The Players.
On August 25, 2006 it was revealed that Manchester United watched the talented Norwegian during a UEFA Cup qualifying game against Drogheda United. He was also rumoured to be wanted by Blackburn Rovers, Bolton Wanderers, West Ham United and Leeds United.
On December 29 2006 it was announced that Wigan Athletic had secured Hæstad on a 6 mounths loan contract. The Wigan boss, Paul Jewell expressed delight on signing the talented midfielder. The Norwegian newspaper VG would later reveal that it not was a standard loan contract, but an intricate deal that could see Hæstad stay at Wigan until July 2010, if they pick up an option to buy him at the end of the current season. Hæstad made his Premier League debut on January 13, 2007 against Chelsea, but was released from his loan contract at Wigan Athletic by mutual consent on 1 April 2007.
Hæstad made a scoring return for IK Start on his return to Norway after scoring the fourth goal in a 4-2 victory away to Aalesund