"James inherited plenty of money, so he didn't need a well-paid profession."
-- J.K. Rowling (AOL)
The Sleekeazy’s Hair Potion Company was founded by Fleamont Potter, grandfather of Harry Potter and the inventor of Sleekeazy’s Hair Potion, which “quadrupled the family gold.” When he retired he sold the company for a “vast profit” which added to the family fortune in the family vault at Gringotts (WW).
Fleamont was a descendent of Linfred of Stinchcomb, who invented Skelegrow and the Pepperup Potion (WW).
James Potter, son of Fleamont, did not work in the family company since it was sold before he was born. After he graduated from Hogwarts and married Lily Evans they lived on inherited wealth (AOL, OBT/CH).
Hermione used Sleekeazy's Hair Potion when she got dressed up for her date with Viktor Krum at the Yule Ball. However, her hair was soon bushy again (GF24).
When Harry saw Snape's memory of James Potter, he definitely seemed rather obsessed with tossing his hair around, perhaps a small rebellion against a family famous for their "sleek" hair potion: "Harry noticed that his father had a habit of rumpling up his hair as though to keep it from getting too tidy." Harry's future mother Lily also accused James of "messing up" his hair to make it look windswept, as if he just got off a broomstick (OP28).
Hermione likely used Sleekeazy's Hair Potion again when preparing for Bill and Fleur's wedding. Her hair is described as "sleek and shiny," which along with a floaty, lilac-colored dress and heels, elited quite a reaction from Ron:
Wow,” he added, blinking rather rapidly as Hermione came hurrying toward them. “You look great!”
“Always the tone of surprise,” said Hermione, though she smiled (DH8).
Fleamont Potter was a successful potioneer like his ancestor Lindfred of Stinchcombe.