diff --git a/Userland/Applications/SystemMonitor/ProcessModel.cpp b/Userland/Applications/SystemMonitor/ProcessModel.cpp
index 9b6e45b9cc..3498a6be68 100644
--- a/Userland/Applications/SystemMonitor/ProcessModel.cpp
+++ b/Userland/Applications/SystemMonitor/ProcessModel.cpp
@@ -226,7 +226,7 @@ GUI::Variant ProcessModel::data(GUI::ModelIndex const& index, GUI::ModelRole rol
         case Column::Name:
             return thread.current_state.name;
         case Column::Command:
-            return thread.current_state.command;
+            return thread.current_state.command.visit([](String const& cmdline) { return cmdline; }, [](auto const&) { return ""_short_string; });
         case Column::Syscalls:
             return thread.current_state.syscall_count;
         case Column::InodeFaults:
@@ -296,7 +296,7 @@ GUI::Variant ProcessModel::data(GUI::ModelIndex const& index, GUI::ModelRole rol
                 return DeprecatedString::formatted("{} (*)", thread.current_state.name);
             return thread.current_state.name;
         case Column::Command:
-            return thread.current_state.command;
+            return thread.current_state.command.visit([](String const& cmdline) { return cmdline; }, [](auto const&) { return ""_short_string; });
         case Column::Syscalls:
             return thread.current_state.syscall_count;
         case Column::InodeFaults:
@@ -422,25 +422,16 @@ Vector<GUI::ModelIndex> ProcessModel::matches(StringView searching, unsigned fla
     return found_indices;
 }
 
-static ErrorOr<DeprecatedString> try_read_command_line(pid_t pid)
+ErrorOr<String> ProcessModel::read_command_line(pid_t pid)
 {
-    auto file = TRY(Core::File::open(DeprecatedString::formatted("/proc/{}/cmdline", pid), Core::File::OpenMode::Read));
+    auto file = TRY(Core::File::open(TRY(String::formatted("/proc/{}/cmdline", pid)), Core::File::OpenMode::Read));
     auto data = TRY(file->read_until_eof());
     auto json = TRY(JsonValue::from_string(StringView { data.bytes() }));
     auto array = json.as_array().values();
-    return DeprecatedString::join(" "sv, array);
+    return String::join(" "sv, array);
 }
 
-static DeprecatedString read_command_line(pid_t pid)
-{
-    auto string_or_error = try_read_command_line(pid);
-    if (string_or_error.is_error()) {
-        return "";
-    }
-    return string_or_error.release_value();
-}
-
-ErrorOr<void> ProcessModel::initialize_process_statistics_file()
+ErrorOr<void> ProcessModel::ensure_process_statistics_file()
 {
     if (!m_process_statistics_file || !m_process_statistics_file->is_open())
         m_process_statistics_file = TRY(Core::File::open("/sys/kernel/processes"sv, Core::File::OpenMode::Read));
@@ -450,7 +441,7 @@ ErrorOr<void> ProcessModel::initialize_process_statistics_file()
 
 void ProcessModel::update()
 {
-    auto result = initialize_process_statistics_file();
+    auto result = ensure_process_statistics_file();
     if (result.is_error()) {
         dbgln("Process model couldn't be updated: {}", result.release_error());
         return;
@@ -489,6 +480,8 @@ void ProcessModel::update()
                 auto thread_data = m_threads.ensure(tid, [&] { return make_ref_counted<Thread>(process_state); });
                 thread_data->previous_state = move(thread_data->current_state);
                 thread_data->current_state = move(state);
+                thread_data->read_command_line_if_necessary();
+
                 if (auto maybe_thread_index = process_state.threads.find_first_index(thread_data); maybe_thread_index.has_value()) {
                     process_state.threads[maybe_thread_index.value()] = thread_data;
                 } else {
@@ -511,7 +504,6 @@ void ProcessModel::update()
                     state.kernel = process.kernel;
                     state.executable = process.executable;
                     state.name = thread.name;
-                    state.command = read_command_line(process.pid);
                     state.uid = process.uid;
                     state.state = thread.state;
                     state.user = process.username;
@@ -554,7 +546,6 @@ void ProcessModel::update()
                 state.kernel = process.kernel;
                 state.executable = process.executable;
                 state.name = process.name;
-                state.command = read_command_line(process.pid);
                 state.uid = process.uid;
                 state.state = "Zombie";
                 state.user = process.username;
diff --git a/Userland/Applications/SystemMonitor/ProcessModel.h b/Userland/Applications/SystemMonitor/ProcessModel.h
index 6909196d96..9f6a9f9d7f 100644
--- a/Userland/Applications/SystemMonitor/ProcessModel.h
+++ b/Userland/Applications/SystemMonitor/ProcessModel.h
@@ -55,6 +55,8 @@ public:
         __Count
     };
 
+    static ErrorOr<String> read_command_line(pid_t pid);
+
     static ProcessModel& the();
 
     static NonnullRefPtr<ProcessModel> create() { return adopt_ref(*new ProcessModel); }
@@ -94,6 +96,11 @@ private:
 
     struct Process;
 
+    enum class EmptyCommand : u8 {
+        NotInitialized,
+        PermissionError,
+    };
+
     struct ThreadState {
         pid_t tid { 0 };
         pid_t pid { 0 };
@@ -105,7 +112,7 @@ private:
         bool kernel { false };
         DeprecatedString executable { "" };
         DeprecatedString name { "" };
-        DeprecatedString command { "" };
+        Variant<String, EmptyCommand> command { EmptyCommand::NotInitialized };
         uid_t uid { 0 };
         DeprecatedString state { "" };
         DeprecatedString user { "" };
@@ -202,6 +209,26 @@ private:
         {
             return current_state.tid == current_state.process.pid;
         }
+
+        void read_command_line_if_necessary()
+        {
+            // Most likely the previous state still has a command line which we can copy over.
+            // Or, reading the command line was not allowed, e.g. on a Kernel process.
+            if ((previous_state.command.has<String>() && !current_state.command.has<String>())
+                || (previous_state.command.has<EmptyCommand>() && previous_state.command.get<EmptyCommand>() == EmptyCommand::PermissionError)) {
+                current_state.command = previous_state.command;
+                return;
+            }
+
+            auto maybe_command_line = read_command_line(current_state.pid);
+            if (!maybe_command_line.is_error()) {
+                current_state.command = maybe_command_line.value();
+                previous_state.command = maybe_command_line.release_value();
+            } else if (maybe_command_line.error().code() == EPERM || maybe_command_line.error().code() == EACCES) {
+                current_state.command = EmptyCommand::PermissionError;
+                previous_state.command = EmptyCommand::PermissionError;
+            }
+        }
     };
 
     struct Process {
@@ -240,7 +267,7 @@ private:
 
     int thread_model_row(Thread const& thread) const;
 
-    ErrorOr<void> initialize_process_statistics_file();
+    ErrorOr<void> ensure_process_statistics_file();
 
     OwnPtr<Core::File> m_process_statistics_file;