Grosenick was born and raised in the Milwaukee/Waukesha suburb of
Brookfield, Wisconsin, where he attended
Brookfield East High School and graduated in 2007. He then went on to play with Team Illinois' Midget Major team for a year, and eventually ended up playing for the
Cedar Rapids RoughRiders for two years before heading off to play for
Union College in New York. Grosenick played for the
Union Dutchmen in the
NCAA Men's Division I ECAC Hockey conference. In his
sophomore year (2011–2012), Grosenick's outstanding play was recognized when he won the
Ken Dryden Award as the ECAC Goaltender of the Year, and was selected to the 2011–12 ECAC First Team All-League. He was also named a First-Team AHCA All-American and was a
Hobey Baker Award Finalist. On April 8, 2013, following his third year at Union, Grosenick signed a one-year entry-level contract with the San Jose Sharks. On November 12, 2014, Grosenick was called up after goalie
Alex Stalock was placed on injured reserve. He made his NHL debut on November 16, 2014 against the
Carolina Hurricanes where he went on to record a 45-save 2–0 shutout, becoming the 22nd goalie to record a shutout in their debut, and at the same time setting a record for most saves in a shutout debut in the modern era. Grosenick was recalled once more on January 3, 2016 when Alex Stalock was sent down to the Sharks'
AHL affiliate, the
San Jose Barracuda, on a conditioning assignment. He was re-signed by San Jose on June 5, 2017. On February 25, 2018, Grosenick along with
Brandon Bollig were traded to the
Nashville Predators in exchange for a sixth round draft pick in
2018. Grosenick started the
2018–19 season with the Milwaukee Admirals before being recalled by the Predators on October 22. He was reassigned to Milwaukee on October 31. On March 1, 2019, after posting a 14–12–3 record, Grosenick signed a one-year, two-way contract with the Predators. On October 9, 2020, Grosenick was signed as a free agent to a one-year, two-way contract with the
Los Angeles Kings. After attending the Kings training camp, Grosenick initially made the Kings roster, serving as the backup in their opening
2020–21 season game before he was placed on waivers. He was subsequently claimed the following day by the
Edmonton Oilers on January 16, 2021. Added by the Oilers as insurance with an injury to veteran
Mike Smith, Grosenick remained on the Oilers roster without making an appearances until he was subsequently re-claimed by the Kings off waivers on February 6, 2021. He was immediately assigned to AHL affiliate, the Ontario Reign. On March 10, 2021, Grosenick was called back up to the Kings to make his first NHL start since the 2014–15 season, against the
Anaheim Ducks. He made 33 saves for the Kings and earned his second career victory in a 5–1 victory. As a free agent following his lone season with the Kings, Grosenick was signed to a one-year, two-way contract with the
Boston Bruins on July 28, 2021. After a standout season within the Bruins organization, Grosenick left as a free agent and was signed to a one-year, $750,000 contract with the
Philadelphia Flyers on July 13, 2022. In the following season, Grosenick was assigned to AHL affiliate, the
Lehigh Valley Phantoms and was limited to just 6 games through injury. On July 1, 2023, having concluded his contract with the Flyers, Grosenick was signed to a one-year, two-way contract in a return to former club, the
Nashville Predators, for the season. At the conclusion of his contract within the Predators organization, Grosenick left as a free agent and was signed to a one-year, two-way contract with the Minnesota Wild on July 1, 2024. On October 1, 2024 it was announced that he would miss the entirety of the season due to injury. ==Career statistics==