Manziel, the 22nd overall selection in the draft, will compete with Brian Hoyer to be the team's starting quarterback.
Terms were not released, but the NFL rookie wage scale projected Manziel's deal to be worth about $8.25 million for four years. Like all first-round picks, his contract also includes a fifth-year team option.
Manziel's NFL income may actually pale in comparison to his endorsement income, especially from Nike. Manziel signed a multiyear deal with Nike in March, and the company very soon after started selling Manziel apparel similar to what he wore at his NFL pro day workout in front of fans. Maverick Carter, the marketing manager for LeBron James' management team of LRMR, is representing Manziel for his marketing and endorsement deals.
Manziel threw for 7,820 yards with 63 touchdowns and 22 interceptions in two seasons at Texas A&M. He also ran for 2,160 yards and had 30 touchdowns. In his first season in 2012, he became the first freshman to win the Heisman Trophy.
But when Browns training camp opens in late July, he will have to win the starting job. Browns coach Mike Pettine already has said Hoyer will be the starter when training camp opens.