In 1989, Loewenstein was recruited by Eric Gaffney to play drums and bass for Sebadoh. His first songwriting contributions came on Sebadoh III and continued on Bubble & Scrape, adding "dark.. rough hewn pop gems" like "Happily Divided" and "Sister". Following Gaffney's departure from Sebadoh in 1993, Loewenstein assumed a higher songwriting profile, contributing five songs to 1994's Bakesale. This continued on the last two Sebadoh releases Harmacy and The Sebadoh, after which the group went on hiatus until 2003/2004 when he and Lou Barlow toured as a duo on a tour they called "Turbo Acoustic", with Loewenstein and Barlow playing along to drum tracks that were pre-recorded by Loewenstein. In 2007, he, Barlow and Gaffney reformed the "Sebadoh Classic" trio and toured throughout the United States and Europe.
Solo work
Loewenstein's first official solo work came under the name of Sparkalepsy with the Heather's Overbite EP, released in 1994. In 2002, he produced and played every instrument on his first solo albumAt Sixes and Sevens, which was released on Sub Pop. The touring band for that record included Bob D'Amico, who would later join Jason in playing with the Fiery Furnaces in addition to forming Circle of Buzzards with him in 2008, as well as eventually joining Sebadoh when they reformed in 2011. In late 2016 it was announced that Jason would be releasing a new solo record on Joyful Noise Recordings titled Spooky Action. A single for the song Machinery was released before the release date of June 16 2017 was announced. The album was promoted partly through a tour of small DIY house shows throughout the South and the Midwest with a backing band featuring Bob D'Amico and Matthew Friedberger.
Fiery Furnaces
From August 2005 to the present, Jason has performed and recorded with the Brooklyn-based band The Fiery Furnaces, playing bass and guitar. He acted as engineer on their 2008 release Remember and 2009's I'm Going Away.
Other work
He has also played drums on several albums including Will Oldham's album Viva Last Blues, David Kilgour's "Frozen Orange", Brett Eugene Ralph's "Kentucky Chrome Review", and Lou Barlow's "EMOH".
