McCobb was born in Medford, Massachusetts to Raymond and Winifred McCobb. Both his father and mother were born in Massachusetts although neither family originated there. His father's family being from Maine and his mother's family from Ireland. His father was employed in 1920 as a Salesman in "Men's Furnishings".
Knowing from a very early age that he wanted to be an artist, McCobb studied art, drawing and painting at the Vesper George School of Art in Boston, although he did not complete his course there.
Best known for his furniture designs he also designed radios and televisions for CBS-Columbia, Hi-Fi Consoles for Bell & Howell, along with other household items.
His Planner Group, manufactured by Winchendon Furniture Company, was among the best selling contemporary furniture lines of the 1950s and was in continuous production from 1949 until 1964.
Other well-known furniture lines designed by McCobb include Predictor by O’Hearn Furniture, The Irwin Group by Calvin Furniture, The Connoisseur Collection by H. Sacks and Sons, The Calvin Group by Calvin Furniture, and Directional by Calvin Furniture.