Mercer means merchant, fitting in with other occupational names in fashion such as Cooper and Fletcher. It has a long history of use as both a first and last name.
My first association is Mercer Mayer, who is a children’s author and illustrator. Growing up I loved his Little Critter books. We also had a couple Little Monster books, but I preferred the critter. Especially the books with little critter’s little sister. Mercer Mayer has had over 300 books published. Not bad for someone that was told by several authority figures he wasn’t good enough to ever make money with his illustrations.
Johnny Mercer was a songwriter and the founder of Capital Records. James Mercer is the lead singer and guitarist of The Shins. Writer and social activist Langston Hughes was born James Mercer Langston Hughes.
I think Merce is a phenomenal nickname, and it reminds me of Merce Cunningham. Merce was a dancer and choreographer who was very influential in the world of modern dance. Extremely talented and extremely dedicated, he continued running the Cunningham Dance Foundation and creating new art until he died at age 90.