diff --git a/config/src/config.rs b/config/src/config.rs
index f40dafa68..c31d9cf87 100644
--- a/config/src/config.rs
+++ b/config/src/config.rs
@@ -1538,18 +1538,29 @@ impl Config {
             }
         };
 
-        self.apply_cmd_defaults(&mut cmd, default_cwd);
+        self.apply_cmd_defaults(&mut cmd, None, default_cwd);
 
         Ok(cmd)
     }
 
-    pub fn apply_cmd_defaults(&self, cmd: &mut CommandBuilder, default_cwd: Option<&PathBuf>) {
+    pub fn apply_cmd_defaults(
+        &self,
+        cmd: &mut CommandBuilder,
+        default_prog: Option<&Vec<String>>,
+        default_cwd: Option<&PathBuf>,
+    ) {
         // Apply `default_cwd` only if `cwd` is not already set, allows `--cwd`
         // option to take precedence
         if let (None, Some(cwd)) = (cmd.get_cwd(), default_cwd) {
             cmd.cwd(cwd);
         }
 
+        if let Some(default_prog) = default_prog {
+            if cmd.is_default_prog() {
+                cmd.replace_default_prog(default_prog);
+            }
+        }
+
         // Augment WSLENV so that TERM related environment propagates
         // across the win32/wsl boundary
         let mut wsl_env = std::env::var("WSLENV").ok();
diff --git a/mux/src/domain.rs b/mux/src/domain.rs
index a10fa216e..c0a59048c 100644
--- a/mux/src/domain.rs
+++ b/mux/src/domain.rs
@@ -453,23 +453,25 @@ impl LocalDomain {
         pane_id: PaneId,
     ) -> anyhow::Result<CommandBuilder> {
         let config = configuration();
+
+        let wsl = self.resolve_wsl_domain();
+        let default_prog = wsl
+            .as_ref()
+            .map(|wsl| wsl.default_prog.as_ref())
+            .unwrap_or(config.default_prog.as_ref());
+
         let mut cmd = match command {
             Some(mut cmd) => {
-                config.apply_cmd_defaults(&mut cmd, config.default_cwd.as_ref());
+                config.apply_cmd_defaults(&mut cmd, default_prog, config.default_cwd.as_ref());
                 cmd
             }
-            None => {
-                let wsl = self.resolve_wsl_domain();
-                config.build_prog(
-                    None,
-                    wsl.as_ref()
-                        .map(|wsl| wsl.default_prog.as_ref())
-                        .unwrap_or(config.default_prog.as_ref()),
-                    wsl.as_ref()
-                        .map(|wsl| wsl.default_cwd.as_ref())
-                        .unwrap_or(config.default_cwd.as_ref()),
-                )?
-            }
+            None => config.build_prog(
+                None,
+                default_prog,
+                wsl.as_ref()
+                    .map(|wsl| wsl.default_cwd.as_ref())
+                    .unwrap_or(config.default_cwd.as_ref()),
+            )?,
         };
         if let Some(dir) = command_dir {
             cmd.cwd(dir);
diff --git a/mux/src/ssh.rs b/mux/src/ssh.rs
index 157d887ec..80bf13e58 100644
--- a/mux/src/ssh.rs
+++ b/mux/src/ssh.rs
@@ -253,7 +253,7 @@ impl RemoteSshDomain {
         let config = config::configuration();
         let cmd = match command {
             Some(mut cmd) => {
-                config.apply_cmd_defaults(&mut cmd, None);
+                config.apply_cmd_defaults(&mut cmd, self.dom.default_prog.as_ref(), None);
                 cmd
             }
             None => config.build_prog(None, self.dom.default_prog.as_ref(), None)?,
diff --git a/pty/src/cmdbuilder.rs b/pty/src/cmdbuilder.rs
index 0a270eae3..675d88cdb 100644
--- a/pty/src/cmdbuilder.rs
+++ b/pty/src/cmdbuilder.rs
@@ -276,6 +276,22 @@ impl CommandBuilder {
         self.args.push(arg.as_ref().to_owned());
     }
 
+    /// If a builder is_default_prog, then this function can be used to
+    /// set the actual prog that should be used.
+    /// This is intended to facilitate plumbing through the handling
+    /// of the underlying default prog when merging together supplemental
+    /// env and cwd information.
+    /// You will not typically use this method in your own code.
+    pub fn replace_default_prog(&mut self, args: impl IntoIterator<Item = impl AsRef<OsStr>>) {
+        if !self.is_default_prog() {
+            panic!("attempted to replace_default_prog on a non-default_prog builder");
+        }
+
+        for arg in args {
+            self.args.push(arg.as_ref().to_owned());
+        }
+    }
+
     /// Append a sequence of arguments to the current command line
     pub fn args<I, S>(&mut self, args: I)
     where