He went on to gain substantial experience in banking, and was elected to the North Palm Beach Village Council in 1993.

In 2000, Atwater ran for the Florida House of Representatives from the 83rd District, defeating Democratic nominee Pam Dunston and independent Michael I. Danchuk.

After just two years in the House, he ran for the Florida Senate from the 25th District, which included Palm Beach and Broward counties.

Unopposed in the primary election, Atwater faced off against long-serving Democratic Attorney General of Florida Bob Butterworth in the general election, and, aided by then-Governor Jeb Bush's strong performance that year, defeated Butterworth by a solid margin.

In the general election, Atwater faced off against former State Representative Loranne Ausley, whom he defeated by 18 percentage points.