Scholars have exerted some energy attempting to disprove a few claims made for Kerll; he did not, apparently, study with Frescobaldi, although he may have had contact with Froberger. Furthermore, there's no evidence to support the assertion that Kerll served as organist at the Stephansdom, a leading church in Vienna. What is certain is that Kerll got his first lessons from his organist father, and was writing music by the time he was 14. More formal studies came in Vienna in the 1640s under Giovanni Valentini, and in Rome in the late 1640s and early 1650s with Carissimi. By age 20, Kerll was proficient enough to land a job as organist at the Brussels court of Archduke Leopold Wilhelm, who subsidized his lessons with Carissimi.
Now thoroughly trained and not merely talented, Kerll obtained the vice-Kapellmeister post at the court of Elector Ferdinand Maria in Munich in 1656; he rose to full Kapellmeister in six months, upon the death of his predecessor. The following year it was Kerll who wrote the very first work, Oronte, performed at the new Munich opera house. This and Kerll's 10 other operas have all been lost. The year 1658 brought another prestigious assignment: the mass for the coronation of Emperor Leopold I at Frankfurt. The emperor elevated the peasant-born Kerll to the nobility in 1664.
Kerll's career, however, was not one long, easy ascent. He fought with the Italian singers at the Munich court, and in 1673 he quit his job and moved to Vienna. How he initially supported himself there is unclear, but Leopold did grant him a pension in 1675 and made him one of his court organists two years later. Kerll survived both the plague of 1679 and the siege of Vienna in 1683, commemorating them both in music, and then returned to Munich for about the last decade of his life, publishing there some of his organ and sacred music. Kerll is praised perhaps less for his own qualities than for his capability as a successor to Froberger and forerunner of Bach, particularly in the area of organ counterpoint. Most of his masses employ the then-fashionable concertante technique.