He was born August 28, 1841, at West Point, New York, and studied with his father Robert Walter Weir and at the National Academy, New York. As a young man, he worked on still life paintings and became proficient at landscapes. In 1862, around the time of his 21st birthday, he was commissioned by the art patron Robert Leighton Stuart to paint a landscape scene of West Point which he named "Hudson Highlands, West Point, Summer Afternoon". It is also known as "View of the Hudson Highlands, West Point". This commission introduced him to the art world of New York City, and led to his renting a small room in the Tenth Street Studio, where he became acquainted with many of the rising young artists of the day.