(covers information from several alternate timelines)
Walsh would later remain aboard Enterprise during the vessel's search for the Xindi weapon throughout that year.
In April, he was working in the situation room of the bridge when Suliban soldiers kidnapped Captain Archer. Later, he was working in a corridor and passed by Trip Tucker and Malcolm Reed while Enterprise underwent repairs in a drydock orbiting Earth. Walsh was back on the bridge when Enterprise entered the Delphic Expanse and was attacked by three Klingon Bird-of-Prey under the command of Duras, son of Toral. (ENT: "The Expanse")
He was working in the situation room on the bridge when T'Pol informed Captain Archer about the results of the Xindi finger. During the absence of Lieutenant Reed on his away mission to a trellium mining planet, Walsh worked as relief tactical officer. Later, he passed Reed and Trip Tucker in a corridor. (ENT: "The Xindi")
Walsh was part of the security detail who went with Captain Archer to the transporter alcove where they arrested Rajiin. He was ordered by Archer to take her to the brig where he stood guard until Captain Archer came to interrogate Rajiin. When Archer left due to the attacking Xindi-Reptilians, Walsh was ordered to take some men and guard the brig as Rajiin became the target of the Xindi-Reptilians. When a group of three boarding Xindi-Reptilians fired an organic grenade, Walsh was hit by several darts but survived. The other two security crewmen were killed. (ENT: "Rajiin")
In an alternate timeline in which Captain Archer was infected by interspatial parasites, Walsh was one of the two crewmen on the bridge who tried to remove Archer from the bridge and bring him back into his quarters at the order of Captain T'Pol. (ENT: "Twilight")
In an alternate version of 1944, Walsh assisted Commander Trip Tucker to repair one of the starship's shuttlepods, which had been damaged in an attack by a squadron of P-51 Mustangs. In order to repair the craft, the shuttlepod required a new EPS conduit. Tucker asked Walsh to retrieve a replacement conduit from the injector assembly in engineering. (ENT: "Storm Front")
Background information Edit
Ensign Walsh was portrayed by regular background actor and Paramount Pictures set security Duncan K. Fraser. Fraser received no credit for his appearances as Walsh except for the fourth season episode "Bound", where he was credited as "Crewman #2".