diff --git a/src/components/IdentitySheet.tsx b/src/components/IdentitySheet.tsx
new file mode 100644
index 00000000..081e53de
--- /dev/null
+++ b/src/components/IdentitySheet.tsx
@@ -0,0 +1,205 @@
+import React from 'react';
+import {
+  View, Text, StyleSheet, ScrollView, Pressable, Modal, Animated, Easing,
+} from 'react-native';
+import { useSafeAreaInsets } from 'react-native-safe-area-context';
+import { X, Check, Mail } from 'lucide-react-native';
+import { spacing, radius, typography, type ThemePalette } from '../theme/tokens';
+import { useColors } from '../theme/colors';
+import { useSheetDrag } from '../lib/use-sheet-drag';
+import type { Identity } from '../api/types';
+import { useLocaleStore } from '../stores/locale-store';
+
+interface IdentitySheetProps {
+  visible: boolean;
+  onClose: () => void;
+  identities: Identity[];
+  selectedIdentityId: string | null;
+  onPick: (identity: Identity) => void;
+}
+
+export function IdentitySheet({
+  visible, onClose, identities, selectedIdentityId, onPick,
+}: IdentitySheetProps) {
+  const c = useColors();
+  const styles = React.useMemo(() => makeStyles(c), [c]);
+  const insets = useSafeAreaInsets();
+  const slideY = React.useRef(new Animated.Value(500)).current;
+  const overlayOpacity = React.useRef(new Animated.Value(0)).current;
+  const dragHandlers = useSheetDrag({ slideY, closedY: 500, onClose });
+  const { t } = useLocaleStore();
+
+  React.useEffect(() => {
+    if (visible) {
+      Animated.parallel([
+        Animated.timing(slideY, { toValue: 0, duration: 220, easing: Easing.out(Easing.cubic), useNativeDriver: true }),
+        Animated.timing(overlayOpacity, { toValue: 1, duration: 220, useNativeDriver: true }),
+      ]).start();
+    } else {
+      Animated.parallel([
+        Animated.timing(slideY, { toValue: 500, duration: 180, easing: Easing.in(Easing.cubic), useNativeDriver: true }),
+        Animated.timing(overlayOpacity, { toValue: 0, duration: 180, useNativeDriver: true }),
+      ]).start();
+    }
+  }, [visible, slideY, overlayOpacity]);
+
+  return (
+    <Modal visible={visible} transparent animationType="none" onRequestClose={onClose} statusBarTranslucent>
+      <Animated.View style={[styles.sheetOverlay, { opacity: overlayOpacity }]}>
+        <Pressable style={styles.sheetOverlayPress} onPress={onClose} />
+      </Animated.View>
+      <Animated.View
+        style={[
+          styles.sheet,
+          { paddingBottom: Math.max(insets.bottom, spacing.md), transform: [{ translateY: slideY }] },
+        ]}
+      >
+        <View {...dragHandlers}>
+          <View style={styles.sheetHandleHit}>
+            <View style={styles.sheetHandle} />
+          </View>
+          <View style={styles.sheetHeader}>
+            <Text style={styles.sheetTitle}>{t('email_composer.from', 'From')}</Text>
+            <Pressable onPress={onClose} hitSlop={8} style={styles.sheetClose}>
+              <X size={18} color={c.textSecondary} />
+            </Pressable>
+          </View>
+        </View>
+        <ScrollView style={styles.scrollList}>
+          {identities.map((identity) => {
+            const isSelected = identity.id === selectedIdentityId;
+            return (
+              <Pressable
+                key={identity.id}
+                onPress={() => {
+                  onPick(identity);
+                  onClose();
+                }}
+                style={({ pressed }) => [
+                  styles.identityRow,
+                  pressed && styles.identityRowPressed,
+                ]}
+              >
+                <View style={styles.iconWrap}>
+                  <Mail size={16} color={isSelected ? c.primary : c.textSecondary} />
+                </View>
+                <View style={styles.identityDetails}>
+                  {!!identity.name && (
+                    <Text style={styles.identityName} numberOfLines={1}>
+                      {identity.name}
+                    </Text>
+                  )}
+                  <Text style={[styles.identityEmail, !identity.name && styles.identityEmailOnly]} numberOfLines={1}>
+                    {identity.email}
+                  </Text>
+                </View>
+                {isSelected && (
+                  <View style={styles.checkWrap}>
+                    <Check size={16} color={c.primary} />
+                  </View>
+                )}
+              </Pressable>
+            );
+          })}
+        </ScrollView>
+      </Animated.View>
+    </Modal>
+  );
+}
+
+function makeStyles(c: ThemePalette) {
+  return StyleSheet.create({
+    sheetOverlay: {
+      ...StyleSheet.absoluteFillObject,
+      backgroundColor: 'rgba(0,0,0,0.5)',
+    },
+    sheetOverlayPress: { flex: 1 },
+    sheet: {
+      position: 'absolute',
+      left: 0,
+      right: 0,
+      bottom: 0,
+      maxHeight: '60%',
+      backgroundColor: c.popover,
+      borderTopLeftRadius: radius.lg,
+      borderTopRightRadius: radius.lg,
+      borderTopWidth: 1,
+      borderColor: c.border,
+      paddingTop: spacing.sm,
+    },
+    sheetHandleHit: {
+      alignItems: 'center',
+      paddingTop: spacing.xs,
+      paddingBottom: spacing.sm,
+    },
+    sheetHandle: {
+      width: 36,
+      height: 4,
+      borderRadius: 2,
+      backgroundColor: c.border,
+    },
+    sheetHeader: {
+      flexDirection: 'row',
+      alignItems: 'center',
+      justifyContent: 'space-between',
+      paddingHorizontal: spacing.lg,
+      paddingBottom: spacing.sm,
+      borderBottomWidth: 1,
+      borderBottomColor: c.border,
+    },
+    sheetTitle: {
+      ...typography.bodySemibold,
+      color: c.text,
+    },
+    sheetClose: {
+      width: 28,
+      height: 28,
+      alignItems: 'center',
+      justifyContent: 'center',
+      borderRadius: radius.xs,
+    },
+    scrollList: {
+      paddingVertical: spacing.xs,
+    },
+    identityRow: {
+      flexDirection: 'row',
+      alignItems: 'center',
+      paddingHorizontal: spacing.lg,
+      paddingVertical: spacing.md,
+      minHeight: 52,
+    },
+    identityRowPressed: {
+      backgroundColor: c.surfaceHover,
+    },
+    iconWrap: {
+      marginRight: spacing.md,
+      width: 28,
+      height: 28,
+      borderRadius: radius.xs,
+      backgroundColor: c.surface,
+      alignItems: 'center',
+      justifyContent: 'center',
+    },
+    identityDetails: {
+      flex: 1,
+      justifyContent: 'center',
+    },
+    identityName: {
+      ...typography.bodyMedium,
+      color: c.text,
+    },
+    identityEmail: {
+      ...typography.caption,
+      color: c.textSecondary,
+      marginTop: 2,
+    },
+    identityEmailOnly: {
+      ...typography.bodyMedium,
+      color: c.text,
+      marginTop: 0,
+    },
+    checkWrap: {
+      marginLeft: spacing.md,
+    },
+  });
+}
diff --git a/src/components/index.ts b/src/components/index.ts
index d55f3b40..d033bcb7 100644
--- a/src/components/index.ts
+++ b/src/components/index.ts
@@ -5,3 +5,5 @@ export { default as Badge } from './Badge';
 export { Card, SectionHeader, SettingItemRow } from './Card';
 export { default as RadioGroup } from './RadioGroup';
 export { default as Dialog } from './Dialog';
+export { IdentitySheet } from './IdentitySheet';
+
diff --git a/src/screens/ComposeScreen.tsx b/src/screens/ComposeScreen.tsx
index 01d55f4b..0c4b0445 100644
--- a/src/screens/ComposeScreen.tsx
+++ b/src/screens/ComposeScreen.tsx
@@ -17,7 +17,7 @@ import * as FileSystem from 'expo-file-system/legacy';
 import { File as FsFile } from 'expo-file-system';
 import { spacing, radius, typography, componentSizes, type ThemePalette } from '../theme/tokens';
 import { useColors } from '../theme/colors';
-import { Button } from '../components';
+import { Button, IdentitySheet } from '../components';
 import RichTextEditor, {
   type RichTextEditorHandle,
   type RichTextSelectionState,
@@ -26,6 +26,7 @@ import { useEmailStore } from '../stores/email-store';
 import { useContactsStore } from '../stores/contacts-store';
 import { useLocaleStore } from '../stores/locale-store';
 import { useSettingsStore } from '../stores/settings-store';
+import { useAccountStore } from '../stores/account-store';
 import { isGroup } from '../lib/contact-utils';
 import {
   getContactDisplayName,
@@ -260,6 +261,7 @@ export default function ComposeScreen({ route, navigation }: Props) {
   const [identityError, setIdentityError] = React.useState<string | null>(null);
   const [sending, setSending] = React.useState(false);
   const [selectedIdentityId, setSelectedIdentityId] = React.useState<string | null>(null);
+  const [identitySheetOpen, setIdentitySheetOpen] = React.useState(false);
   const [scheduleSheetOpen, setScheduleSheetOpen] = React.useState(false);
   // Custom date/time picker stage. iOS shows one 'datetime' spinner; Android
   // can only show one field at a time, so we walk date → time.
@@ -405,34 +407,35 @@ export default function ComposeScreen({ route, navigation }: Props) {
   // original message (matches webmail's reply-identity behaviour).
   React.useEffect(() => {
     if (selectedIdentityId || identities.length === 0) return;
+    const activeEmail = useAccountStore.getState().getActiveAccount()?.email || jmapClient.username;
+    const defaultIdentity = identities.find(
+      (i) => i.email.toLowerCase() === activeEmail?.toLowerCase()
+    ) ?? identities[0];
+
     if (autoSelectReplyIdentity && replyTo) {
       const candidates = [...(replyTo.to ?? []), ...(replyTo.cc ?? [])];
       const candidateAddrs = new Set(
         candidates.map((r) => r.email?.toLowerCase()).filter(Boolean) as string[],
       );
       const matched = identities.find((i) => candidateAddrs.has(i.email.toLowerCase()));
-      setSelectedIdentityId((matched ?? identities[0]).id);
+      setSelectedIdentityId((matched ?? defaultIdentity).id);
     } else {
-      setSelectedIdentityId(identities[0].id);
+      setSelectedIdentityId(defaultIdentity.id);
     }
   }, [identities, autoSelectReplyIdentity, replyTo, selectedIdentityId]);
 
-  const primaryIdentity =
-    identities.find((i) => i.id === selectedIdentityId) ?? identities[0];
+  const primaryIdentity = React.useMemo(() => {
+    if (identities.length === 0) return null;
+    const activeEmail = useAccountStore.getState().getActiveAccount()?.email || jmapClient.username;
+    const defaultIdentity = identities.find(
+      (i) => i.email.toLowerCase() === activeEmail?.toLowerCase()
+    ) ?? identities[0];
+    return identities.find((i) => i.id === selectedIdentityId) ?? defaultIdentity;
+  }, [identities, selectedIdentityId]);
 
   const openIdentityPicker = () => {
     if (identities.length <= 1) return;
-    Alert.alert(
-      t('email_composer.from', 'From'),
-      undefined,
-      [
-        ...identities.map((i) => ({
-          text: i.name ? `${i.name} <${i.email}>` : i.email,
-          onPress: () => setSelectedIdentityId(i.id),
-        })),
-        { text: t('email_composer.cancel', 'Cancel'), style: 'cancel' as const },
-      ],
-    );
+    setIdentitySheetOpen(true);
   };
 
   const commitTyped = () => {
@@ -1315,6 +1318,14 @@ export default function ComposeScreen({ route, navigation }: Props) {
           onChange={onCustomPickerChange}
         />
       )}
+
+      <IdentitySheet
+        visible={identitySheetOpen}
+        onClose={() => setIdentitySheetOpen(false)}
+        identities={identities}
+        selectedIdentityId={selectedIdentityId}
+        onPick={(identity) => setSelectedIdentityId(identity.id)}
+      />
     </SafeAreaView>
   );
 }