His career with The Who spans more than forty years, during which time the band grew to be considered one of the most influential bands of the rock era and, according to Eddie Vedder, "possibly the greatest live band ever."

Townshend is the primary songwriter for the Who, having written well over one hundred songs for the band's eleven studio albums, including concept albums and the rock operas Tommy and Quadrophenia, plus popular rock and roll radio staples like Who's Next, and dozens more that appeared as non-album singles, bonus tracks on reissues, and tracks on rarities compilations like Odds and Sods. He has also written over one hundred songs that have appeared on his solo albums, as well as radio jingles and television theme songs. Although known primarily as a guitarist, he is also an accomplished singer, keyboardist, and also plays other instruments, such as banjo, accordion, synthesizer, piano, bass guitar and drums, on his own solo albums, several Who albums, and as a guest contributor to a wide array of other artist's recordings. Peter Townshend has never had formal lessons in any of the instruments he plays.

Townshend has also been a contributor and author of newspaper and magazine articles, book reviews, essays, books, and scripts, as well as collaborating as a lyricist (and composer) for many other musical acts. Townshend was ranked #3 in Dave Marsh's list of Best Guitarists in The New Book of Rock Lists #10 in Gibson.com's list of the top fifty guitarists and #50 in Rolling Stone magazine's 2003 list: 100 Greatest Guitarists of All Time.