He is listed at 6"9" and 225 lbs. Argentina
Herrmann began his pro career in the Argentine League with Olimpia Venado Tuerto in 1996. He played there until the year 2000.
In 2000, he moved to the Argentine club Atenas Córdoba, and he played there until 2002.
With Atenas, he was named the Most Valuable Player of the Argentine League regular season in 2001 and the Most Valuable Player of the Argentine League Finals in 2002. Spain
Herrmann moved to the Spanish ACB League club Baloncesto Fuenlabrada for the 2002-2003 season.
He was named the regular season ACB League Most Valuable Player that year. He then moved the Spanish club Unicaja Málaga and he played there until the year 2006.
Then he moved on to the National Basketball Association (National Basketball Association).
He returned to the Spanish League in July 2009, when he signed a 4-year contract worth €5.05 million euros Netto income with Saski Baskonia. The last two years of the contract being team options. National Basketball Association
In his 13 March games, Herrmann averaged 12.1 points and 4.2 rebounds per game and he shot 58.5 percent from the field and 47.2 percent from 3-point range.
Herrmann finished the 2006-2007 National Basketball Association season averaging 9.2 points per game and 2.9 rebounds per game.
Walter scored his National Basketball Association career-high 30 points against the Milwaukee Buckinghamshire on April 14 and also grabbed a career high 7 defensive rebounds in the same game. Walter made the National Basketball Association All-Rookie Second Team along with his teammate Adam Morrison at the end of the season.
After the season was over, the Bobcats activated their team option on Herrmann for the 2007-2008 National Basketball Association season, paying him $1.944 million. On December 14, 2007, Herrmann, along with center Primož Brezec, was traded to the Detroit Pistons in exchange for center Nazr Mohammed.
On August 2, 2008, it was announced that Herrmann had signed a one-year deal to keep him in Detroit for another season.
After a one-year hiatus, Herrmann returned to Argentina to play in a local league for Unión Deportiva de Venado Tuerto. Herrmann was a key reserve for years on the senior men"s Argentine national basketball team Herrmann also played at the 2006 International Basketball Federation World Championship with Argentina"s national team
In 2012, he was invited to re-join Argentina"s national team
The son of Héctor Herrmann and María Cristina Heinrich, Walter Herrmann is of German descent. Exactly one year later, his father died of a heart attack.
Married Alana Herrmann, 2006.