Goodwin returns to the club after being released from the South Sydney Rabbitohs, bringing 176 games of NRL experience.
He made his NRL debut for the Sharks in 2007 and played nine games for the club before stints at the Bulldogs, Souths and Warrington Wolves.
Goodwin has signed with Cronulla for the rest of the season and is expected to begin training with the club tomorrow.
McDonald joins the Sharks on a two-year deal, having played 96 NRL games for the Roosters, Titans, Dragons and Cowboys.
Injuries hampered the McDonald ‘s 2019 season with the Cowboys and led to his release.
Sharks coach John Morris is keen to see the 26-year old rejuvenate his career.
“Nene has shown some really good signs over the last few months,” Morris told the club website. “He’s getting his life back in order, he’s training really hard, he’s in really good nick.
“We all know the talent that he has and he’ll bring much-needed experience as well as a different body shape to our team. I’m looking forward to getting him match fit and for him to add some depth to our backline.”