He was relegated with every Premier League club he has played for: Crystal Palace (1997–98 season), Wimbledon (1999–2000), Ipswich Town (2001–02), Charlton Athletic (2006–07), and Portsmouth (2009–10).

Ipswich finished fifth in the club's first season back in the Premier League, thus securing a UEFA Cup place.

Ipswich trimmed their squad to save on finances, but Hermann turned down a move to newly promoted West Bromwich Albion at the start of the 2002–03 season – reportedly due to West Bromwich offering him vastly reduced wages compared to what he was currently receiving, and also Hermann not wanting to face another relegation battle.

He was able to move to Charlton outside the Premier League's transfer window as Ipswich were in administration, although he would not be eligible to play for the club for the remainder of that season.

Hermann proved his worth for Charlton after making his debut in a 3–0 home defeat at the hands of Manchester City.

On 25 May 2007, Hermann exercised a clause in his contract with Charlton which allowed him to leave on a free transfer if they were relegated and signed a two-year deal with fellow Premier League club Portsmouth.

[15] Hermann scored two goals in two matches for the second season running in 2009, when he netted with headers against both Liverpool and Manchester City.

On 27 March 2010, Hermann snapped his achilles tendon in an away match against Tottenham Hotspur and was ruled out for the rest of the season.

[16] After the match, Spurs and former Portsmouth manager Harry Redknapp commented, "The game was soured by Hermann's injury.

[19] On 14 January 2012, after a long injury spell and limited playing time, it was announced that Hermann would sign for fellow Championship side Coventry City on a six-month contract.

In an online article, manager Michael Appleton stated "Hermann will come in and train with us towards the end of the week and we will see where he is from a fitness point of view.

Hermann made his debut for Iceland in a June 1996 friendly match against Cyprus, coming on as a substitute for Alexander Högnason.