His association with R.E.M. extends to the mid-1990s Seattle scene, where he first met guitarist Peter Buck, with whom he also plays in Scott McCaughey's The Minus 5. Ken also spent time recording and touring with Lagwagon in the late-1990s, during which he helped craft 1997's Double Plaidinum, adding a unique flair to the band's high-paced melodic brand of punk rock. He has also formed a new band with three Norwegian musicians from the band Briskeby, called The Disciplines.
On December 22, 2007, Stringfellow revealed, via his blog, that he would not be part of R.E.M.'s 2008 tour in support of Accelerate. On mid-2008, Stringfellow visited Serbia and, during his visit, appeared as guest on most of the tracks of the album Nikadjekraj (Neveristheend) by the Serbian rock band Veliki Prezir.
On March 3, 2009 Second Motion Records is set to release the first single from The Disciplines as a digital-only single and limited-edition blue vinyl 7", entitled "Yours For The Taking". The label will release the band's debut album "Smoking Kills" on April 28, 2009 in North America, which will also see the first Worldwide release of the album on Vinyl. In 2010, he worked with Can Can, an Ecuadorian electro-rock band, by producing their third album, Caos. During his stay in Ecuador, he premiered a new song by The Posies called "Licenses to Hide". In 2011 Thick Syrup Records released the compilation album '78 LTD. This album features the track "36 Perfect Ways I Ching of Love" Stringfellow made with Jad Fair of Half Japanese.
He has recently been working in Queanbeyan, Australia, on Hannah Gillespie's follow up to her debut album Growing Up Stupid.
Stringfellow is married to a French band manager, Dominique Sassi, and they have a daughter, Aden, born in May 2004. He was previously married to The Fastbacks' bass player Kim Warnick. They divorced in 1996, after a three-year marriage.