Greenthal was a Greenthal was a senior managing director and a senior advisor at Blackstone. She served as a managing director and held management positions at Credit Suisse, Donaldson Lufkin and Jenrette and Lehman Brothers. She currently serves on the boards of Akamai Technologies, Houghton Mifflin Harcourt and Cars.com. She served as a managing director and held management positions at Credit Suisse, Donaldson Lufkin and Jenrette and Lehman Brothers. She currently serves on the boards of Akamai Technologies, Houghton Mifflin Harcourt and Cars.com.