Karl Christian Ludwig Hofer (also spelled Carl Hofer) was born in Karlsruhe, Germany, on October 11, 1878. Though he is now recognized as an influential German Expressionist, Hofer kept himself apart from established groups such as Die Brucke, even as he credited them with inspiring his evolution into his own style. Being both a proud German and student of controversial art genres that were punishable by the Third Reich, his career and life were often fraught with clashing ideals. Today, Hofer's work is considered among the most important of its time.

After the death of his father just weeks after Hofer's birth, Hofer was sent to live with his aunts and was later placed in an orphanage. Despite this hardship, his early interest in art led to a desire for a formal education. He took up a position as an apprentice at a bookshop at age fourteen, where he worked until his enrollment in 1898 at the Karlsruhe Art Academy. Upon recognition of his talent, he received a scholarship from the fund of the Grand Duke of Baden. 

In 1900 Hofer traveled for the first time to study in Paris, where he would return frequently throughout his career. Hofer became a student of Hans Thoma in 1901 and a year later a student of the painter Leopold von Kalckreuth at the State Academy of Fine Arts in Stuttgart. In 1902 he was offered his first patronage by Swiss entrepreneur Thoedor Reinhardt, a five year contract in which Reinhardt would receive the artist's first three to four paintings of each year. This allowed enough income for the artist and his wife, Mathilde Scheinberger, to move to Rome, and then to Paris. 

Hofer's wife Mathilde had been born into a non-practicing Jewish family, but by the time they married she had joined the Protestant church. The couple had three sons, Karl Johannes Arnold, called Carlino, born in 1904, Titus Wolfgang, born in 1905 (died 1906), and Hans-Rudi, born in 1911. From 1908 to 1913 the Hofer family lived in Paris while Hofer continued to paint and exhibit throughout Italy, France, and Germany, including several shows with leading German Expressionists Erich Heckel, Max Pechstein, Karl Schmidt-Rottluff, and others. At this time, Hofer began to establish an artistic style known for walking the line between representational and non-representational Abstract Expressionism, a point of argument for many of his peers in the art world as he insisted that the distinction between both forms was unecessary to properly inhabit the genre. This would be the point on which his career balanced for the rest of his life. 

The family returned to Berlin in 1913, intending to remain there as Hofer expanded his professional teaching career. However, on a trip to exhibit in France in 1914, the Hofer family was stranded in a seaside village in France with the onset of World War I, and were detained there due to their citizenship. Eventually his wife and children were allowed to return to Germany that same year, but it wasn't until 1917 that Hofer was once again able to leave France. He first moved to Switzerland to wait out the end of the war, at which point he returned in Berlin in 1919. With the end of the war on a global scale, however, the struggle for Germans had taken on a new course. For Hofer, this soon included an in internal struggle. 

1920 saw the beginning of his teaching career with a position at the College of Fine Arts in Charlottenburg. This school eventually merged with the Arts and Crafts Museum to form the United State Schools of Free and Applied Arts. Hofer's work became known internationally and in 1928 he was offered an exhibition at the Carnegie Institute in Philadelphia for the 1928 International Art Exhibition. With the rise of his popularity as an artist so too was scrutiny of his work by the Nazis, who by this time were gaining power in Germany. Hofer, like many artists of the time, spoke out against Hitler's increasingly totalitarian stance. 

While Hofer was adamantly against the social implications of a Hitler regime, he still believed that he had a place in the Germany's art world. Though work like his was continuing to incite violent rhetoric from leading powers, he continued to fight for representation as a patriot artist, even as worldwide opinion of the country began to descend into mistrust. By this time, he and Mathilde had separated, though not divorced, and when he was attacked in Nazi propaganda posters for suspicion of being a Jew due to his marriage to Mathilde, he adamantly rejected the notion and argued that his artwork was "free of Jews". This had no effect on the regime's outlook on his work. In 1937 over 300 of his works were confiscated by the Nazis and eight of his paintings were included in the Nazi "Degenerate Art" exhibition. In 1938 he was expelled from his position at the Prussian Academy of Art, and he was subsequently banned from selling his artwork in Germany. In an attempt to maintain his career as a German citizen, he formally divorced Mathilde and married a woman whose background qualified her as of "aryan" descent, effectively lifting the ban. Mathilde, no longer protected under the "mixed marriage" laws instated by the Nazi regime, was sent in 1939 to the Auschwitz concentration camp, where she died in 1942. In March of 1943 his Berlin studio was bombed, destroying all of the work he had created upon his reinstatment into the German art world, and in November his apartment was also destroyed. 

Once the war was over, Hofer became instrumental in creating the Berlin Academy of Arts and in promoting the work of German artists. By the time of his death of a stroke in 1955, he had recieved an honorary doctorate from the University of Berlin in 1948, and was awarded the Order Pour le mérite for Science and Arts in 1952 and the Great Cross of the Order of Merit of the Federal Republic of Germany in 1953. 

Karl Hofer died on April 3, 1955 in Berlin, Germany.