Christian Valdemar Clausen was born on February 17, 1862, in Copenhagen, Denmark. He was the son of Carl Michael Clausen and Ida Vilhelmine Jantzen. Clausen displayed an early interest in art, leading him to pursue formal education in the field. He studied at the Technical Art School and the Royal Danish Academy of Fine Arts in Copenhagen from 1879 to 1882. He further honed his skills through an apprenticeship at the Laurits Tuxen Art School.

Clausen's career was marked by extensive travel and study. In 1887, he traveled to Paris and Spain with his friend Johan Rohde, which significantly influenced his artistic development. By 1889, he was back in Paris, participating in the World Exhibition, where he received an "Honorable Mention." His work during this period was characterized by a focus on light and atmosphere, often depicting figures illuminated by lamplight or natural light from windows.

Clausen exhibited widely throughout his career. He participated in the Spring Exhibits at Charlottenborg Palace numerous times between 1884 and 1911. His work was also featured in international exhibitions, including the Nordic Art Exhibit in Copenhagen (1888) and the International Art Exhibit in Berlin (1891). In 1900, he exhibited at the Paris World Exhibition, further establishing his reputation as a notable artist.

Christian Valdemar Clausen is best known for his sensitive and atmospheric paintings, which often depict serene indoor scenes with a focus on the effects of light. He was a pioneer in capturing the subtle interplay of light and shadow, bringing a unique depth and warmth to his subjects. Clausen's work remains appreciated for its technical skill and emotional resonance.

Christian Valdemar Clausen passed away on February 26, 1911, in Frederiksberg, Denmark. His legacy continues through his contributions to Danish and European art, with his works held in various collections and museums.