Mercadante replaced his former boss Jamie Steele, who announced that he was stepping down after nine years at the helm at the end of the 2017 season.

“We were extremely pleased with the strength of the candidate pool, and Gary’s ability to articulate a clear, passionate vision for the future success of the lacrosse program made him our top choice,” said Director of Athletics Laura Moliken.

Mercadante has turned the Bears into one of the premier programs in the country. In his second season, Mercadante led Ursinus to a 13-4 record, improving by ten wins in his first season. During the 2019 season, the Bears started 6-0 which included three top-20 wins. Due to the hot start, Ursinus moved into the top-10 of the USILA rankings and climbed as high as No. 8 - their highest ranking in program history. Making their first appearance in the Centennial Conference playoffs since 2016, the Bears took down top-seeded No. 13 Franklin & Marshall in the conference semifinals before defeating No. 8 Gettysburg for the first time ever and win their first Centennial Conference Championship in program history. Meradante led the Bears to the NCAA Tournament, but lost a heartbreaker to Springfield, 16-15.

The Bears were off to another great start under Mercadante in 2020, besting his first season's start by going 7-0 and climbing to as high as No. 6 in the national rankings. The season was stopped short due to the global Coronavirus pandemic.

During his time at Ursinus, Mercadante has captured one Centennial Conference championship. Individually, he has also coached five players to All-America status and six to All-CC honors. He also coached Chase Rondeau to the Inside Lacrosse Division III All-Freshman team. His teams have also found superb off the field success, with players earning Academic All-District, Academic All-Area, and Scholar All-American honors.

The third head coach in program history, Mercadante was an assistant with the Bears from 2009 to 2013, serving as defensive coordinator and managing the substitution box. Mercadante was also the team’s academic, budget, recruiting, and video editing/software coordinator.

Ursinus logged a winning record in three of Mercadante’s four years, including a 9-5 mark in 2013, when the Bears notched their first victory over a nationally ranked team when they defeated No. 18 York College. In 2011, Ursinus reached the Centennial Conference playoffs for the first time in program history; the prior year, Mercadante’s man-down defense ranked eighth in Division III.