Career
He is the goalkeeping coach for Liverpool. Achterberg first signed for Tranmere Rovers in 1998, after a successful trial as a replacement for the Everton bound Steve Simonsen. He was immediately selected for the first team due to an injury to Danny Coyne, making his debut against Swindon Town on 25 September 1998.
Achterberg then secured his place as Rovers" first choice goalkeeper after Coyne was transferred to Grimsby Town in 1999.
Achterberg became part of the giant-killing cup teams that defeated such opponents as Everton, Southampton and other big teams. Achterberg"s proficiency in goal was exemplified by the 20 clean sheets he kept during the 2003-2004 season under the stewardship of Brian Little.
The game finished goalless, but was largely dominated by Millwall and John managed to save a penalty kick from Kevin Muscat, despite having to play through injury. Achterberg"s 2005-2006 season was less successful.
After spending most of the season sidelined with injuries, he was replaced by Steve Wilson and Dino Seremet, who was on loan from Luton Town.
Achterberg"s chances of re-establishing himself as Tranmere"s first choice goalkeeper in 2006-2007 were hampered by the signing and good form of veteran journeyman Gavin Ward. Later in the season, an injury to Ward gave Achterberg a chance, but a re-occurrence of his own injury problems saw him sit out the closing months of the season. Achterberg"s contract expired in May 2007 and he was released by Tranmere on 25 May.
This resulted in uproar from many Tranmere fans, who believed that Achterberg deserved a testimonial match, despite him falling just short of the ten years" service usually required to earn a testimonial at a club
On 31 May, however, he was given a two year coaching and player contract with Tranmere. Achterberg made his 300th Rovers appearance in the opening day game of the 2008-2009 season against Swindon Town.
Achterberg had his testimonial game in 2009 for Tranmere against an Everton XI.
After retiring from playing/coaching in 2009 with Tranmere Rovers, Achterberg joined Liverpool Football Club in June 2009 as a goalkeeping coach of the reserve and academy goalkeepers before being promoted to first-team goalkeeping coach in summer 2011.