Following her collegiate career, Cook played in the pro–amW-League for the Chicago Cobras. The Cobras won the W-League national championship in 2000, with Cook as Most Valuable Player (MVP). They had been national runners-up in 1999.
Women's United Soccer Association (WUSA), the first official professional women's soccer league in the United States, began in 2001. Cook was a fourth-round draft pick (25th overall in the global draft) by the Bay Area CyberRays. In 2001 versatile Cook started five of her 14 regular season appearances. In the championship game she substituted in for the injured playmaker Sissi as the CyberRays beat Atlanta Beat on a penalty shootout.
In December 2001 the CyberRays traded her to Washington Freedom for Michelle French. She started ten of 18 regular season appearances and posted one assist as the Freedom finished third. She featured in her second consecutive championship game but the Freedom lost 3–2 to Carolina Courage.
Ahead of the 2003 season, Cook attended the CyberRays' training camp as a free agent after she was waived by Washington Freedom. The team, now known as the San Jose CyberRays, gave Cook a contract after assessing her in training. She played 11 times, with three starts, posting one assist. In mid-season Cook had been waived again, to accommodate Amanda Cromwell's elevation to the active roster, only to be re-signed by the CyberRays as a reserve player.[3] After the 2003 season, the CyberRays' Tisha Venturini, Kelly Lindsey and Cook all announced their retirement from soccer.[4]