In the 21st century, Reijseger continued his prolific pace. While his fruitful relationship with Winter Winter continued, he also branched out between 2000 and 2002 with recordings on Unorthodox, BUZZ-Records, and Nimbus West. He returned to Winter Winter for 2002's widely celebrated I Love You So Much It Hurts, in duet with Italian pianist Franco D'Andrea. With few exceptions -- two collaborative dates for Leo in which he was a featured guest, and 2011's The Skopje Connection Meets Ernst Reijseger for Losen) -- Reijseger recorded for Winter Winter exclusively over the next 14 years. His 2008 solo cello album Tell Me Everything, is among his most acclaimed. Reijseger also scored Requiem for a Dying Planet, Sounds for Two Films by Werner Herzog - The Wild Blue Yonder - The White Diamond (2006), prompting the famed director to say of him: "He is a magnificent cellist, and he can do anything, anything on his cello. He could play the civil war, the American Civil war on his cello." Reijseger's relationship with Herzog was extensive: he also scored 2005's Rescue Dawn, 2009's My Son, My Son, What Have Ye Done, 2010's Cave of Forgotten Dreams, and 2016's Salt and Fire (all Winter Winter). He also worked with director Martijn Maria Smits on Anvers (2009), C’est Déjà L’été (2010), and Under the Weight of Clouds (2012). He cut two albums with the band BARANÁ in 2010: Elektro Shaman and Xenopolis.
The following year saw the release of Klaarlichte Nacht: Musictheatre through the life and work of poet Herman de Coninck in a trio with pianist Wolfert Brederode and actor and accordionist Felix Strategier. Reijseger celebrated his 60th birthday in 2014 with the release of two recordings including Feature, which offered his works performed by a large ensemble that included himself, accordionist Luciano Biondini, vocalists Mola Sylla and Ceylan Ertem, keyboardist Harmen Fraanje, Purves on percussion and four additional cellists. The following year he released the trio offering Count Till Zen, with Sylla and Fraanje. In 2016, he issued his major work, The Volcano Symphony, with Forma Antiqva under the direction of Aaron Zapico, which paved the way for a further collaboration the following year titled Walking Out. ~ Joslyn Layne, Rovi