In the early books, she shows up as the person who runs poker games, and bonds withe the Rock Chicks.  She's a criminal boss, but with a good heart.  In Rock Chick Renegade, she announces to Jules Lawler and Lee Nightingale that she and Darius Tucker will be leaving their operation behind and going legit, implying that it's at least partially Jules' influence.  Shirleen then gets a job working as Lee's receptionist once Dawn leaves.  She drives a Lincoln Navigator.


"An enormous black woman, with an Afro even bigger than Daisy’s hair (needless to say, it was huge)" - Ashley, Kristen (2011-03-04). Rock Chick Rescue (Kindle Location 7480). 
"a big black woman with an enormous Afro and tawny brown eyes." - Ashley, Kristen (2011-03-04). Rock Chick Redemption (Kindle Location 7408).
"She was black, had beautiful skin a shade darker than mocha and the wildest afro I’d ever seen." Ashley, Kristen (2011-11-13). Rock Chick Reckoning (Kindle Locations 1572-1573).
"She was pretty, middle-aged and hitting it well. She had beautiful mocha skin and the biggest afro I’d ever seen, but it suited her perfectly. She had magnificent eyes." - Ashley, Kristen (2011-12-09). Rock Chick Regret .


She was married to Leon, a terrible husband who also was a the head of a drug-dealing enterprise.  When he died, Shirleen and Darius took over the operation, as well as ran poker games (which are featured in Rock Chick Rescue).