Nicky Whelan began her first TV work as host of the Nickelodeon Channel for 2 weeks back in 2003. She was voted the favorite Nickelodeon host and became more popular in 2004 when she ventured in the world of acting. Her first acting stint was the character of Chrissie in Telemovie, Russell Coight's Celebrity Challenge which was aired in Network Ten. Later on, she had her first regular TV co-hosting job in Coxy's Big Break, a travel series wherein she was able to go to different places around Australia.

In 2005, Nicky Whelan became the host for Network Seven's Melbourne Woman, a show which gives a weekly recall of the social scene of Melbourne, as well as some health and fitness advice, fashion tips and real estate topics. She was also the co-host of Night Racing at Moonee Valley for eight consecutive years. She is also the top favorite in presenting awards and handovers for special events, functions and interviews.

Before making her way into the Australian television scene, Nicky Whelan first worked as a model, in which she posed for various magazines.

In 2007, Nicky Whelan appeared with actor David Spade on The Show Biz Show on Comedy Central. She became good friends with the funny actor, and she as well invited him to the set of the popular Australian show Neighbours, so that he can make cameo in the said soap. Spade however was unable to do so since he didn't have a working visa in the country yet.

In the same year, Nicky Whelan made a special guest appearance in Harrow, London, to support the sustainable transport initiatives that will provide benefits to the environment. She also posed for photographs in support for the It's Up to All of Us campaign in Harrow. Upon being cast in Neighbours, Nicky Whelan became one of the most prominent faces on Australian television.

In the United States, Nicky Whelan starred in the movie Hollywood and Wine alongside David Spade. She also appeared in Halloween H2.